Chemistry Short Question Notes 9th Exercise full Book

Prepared & Composed By: Usman Cheema (0308-6908152) Page 1
M.C.Q’s
Answers
1 A 2 C 3 D 4 D 5 D
6 A 7 D 8 C 9 C 10 A
11 D 12 B 13 C
(Exercise Short Questions)
Q1: How does life exist on earth?
Ans: Life exists on earth due to presence of equilibrium phenomenon taking place in
atmosphere.
Example: A natural process in which we take oxygen and exhale (CO₂)
Q2: How different environmental systems can exist?
Ans: Many environmental systems depend for their existence on delicate equilibrium
phenomenon.
Q3: Define Reactants?
Ans: Substances that combine during a chemical reaction are called Reactants.
Q4: Define Products?
Ans: New substances form in a chemical reaction is called Products.
Q5: Give an example of reactants and products?
Ans: Consider the reaction:
2H₂ + O₂ 2H₂O
In above reaction H₂, O₂ are reactants while H₂O is a product.
Q6: What are Irreversible reactions? Give few characteristics of them?
Ans: “Those reactions in which products do not recombine to form reactants are called
Irreversible reactions.”
Characteristics:
(i) These reactions proceed in one direction only.
(ii) Reactants are completely converted into products.
(iii) It is represented by a single arrow between the reactants and products.
Q7: Define Chemical Equilibrium State?
Ans: When the rate of forward reaction takes place at the rate of reverse reaction, the
composition of the reaction mixture remains constant; it is called Chemical Equilibrium
State.
Q8: Give the Characteristics of Reversible reaction?
Ans: Reversible Reaction shows Following Characteristics: -
(i) Products recombine to form reactants.
(ii) It proceeds in both ways.
(iii) Reaction never goes to completion in reversible reaction.
(iv) It attains the dynamic equilibrium.
(v) Maximum yield of the products is obtained.
Chemical
Equilibrium
CHAPTER
9

Q9: How Dynamic equilibrium is established?
Ans: If a reversible reaction is allowed to continue for considerable time without
changing the conditions and rates of forward reaction and rate of reverse reaction
becomes equal but take place in opposite directions this is called dynamic equilibrium.
Q10: Why at equilibrium state reaction does not stop?
Ans: It is because of dynamic equilibrium.
Q11: Why equilibrium state is attainable from either way?
Ans: The concentration of specie at equilibrium stage attains the same values whether
we start the reaction in the vessel in the forward direction or backward direction.
Q12: What is relationship between Active mass and Rate of reaction?
Ans: Active mass represents the concentration in mole dm¯³ and it is expressed as
square brackets ( ). Rate of reaction is change in concentration of reactant or product
divided by the time taken to the change. It is expressed as R=∆c/∆t. So, when active
mass of substance change then rate also change.
Q13: Derive the equilibrium constant expression for the synthesis of ammonia
from nitrogen and hydrogen?
Ans: The reaction for synthesis of ammonia is as:
N₂ + 3H₂ 2NH₃
Rf = Kf [N₂][H₂]³
Rr = Kr [NH₃]²
The expression for equilibrium constant of reaction is:
Kc = [NH₃]²
[N₂][H₂]³
Q14: Write the equilibrium constant expression for two following reaction:-
(i) H₂ + I₂ 2HI
Ans: Rf = Kf [H₂][I₂] = Rate of forward reaction
Rr = Kr [HI]² = Rate of reverse reaction
Kc = [HI]² = Equilibrium constant expression
[H₂][I₂]
(ii) CO + 3H₂ CH₄ + H₂O
Ans: Rf = Kf [CO][H₂]³ = Rate of forward reaction
Rr = Kr [CH₄][H₂O] = Rate of reverse reaction
Kc = [CH₄][H₂O] = Equilibrium constant expression
[CO][H₂]³
Q15: How direction of a reaction can be predicted?
Ans: Direction of chemical reaction at any particular moment can be predict by knowing
the numerical values of equilibrium constant of a chemical reaction and comparing this
with reaction quotient.
Q16: How can you know that a reaction has achieved an equilibrium state?
Ans: If the value of forward becomes equal to reverse the reaction is said to in
equilibrium state thus, Qc = Kc such reactions have comparable amounts of reactants
and products at equilibrium position.
Q17: What are the characteristics of a reaction that establish equilibrium state at
once?
Ans: There are following important characteristics of such reactions:
(i) The reaction is reversible.
(ii) Rates of forward and reverse reaction become equal.
(iii) Amount of reaction and products remains the same.
(iv) It can be disturbed and achieved again under specific
condition.

Q18: If reaction quotient Qᴄ of a reaction is more than Kᴄ what will be the direction
of reaction?
Ans: If reaction quotient Qc is large than equilibrium Kc the reaction will go from right to
left.
Q19: An industry was established based on reversible reaction……..reasons of its
failure being a chemist?
Ans: There are following certain reasons of failure of reaction:
(i) Reaction is reversible so, products recombine to form reactants and dynamic
equilibrium is established.
(ii) Reaction condition like temperature, pressure and catalyst are not satisfied.
Q20: Define Static Equilibrium. Give example?
Ans: When reaction ceases to proceed it is called Static Equilibrium. It occurs in physical
phenomenon.
Example: A building remains standing rather than falling down.
Q21: Why do rates of forward reactions slows down when reversible reaction
approaches the equilibrium stage?
Ans: As reaction proceed, concentration of reactants decreases with time, so rate of
reaction slows down gradually.
Q22: Under what conditions Kᴄ has no units?
Ans: When number of moles of reactants and products are equal then Kc has no units.
H₂ + I₂ 2HI
Kc = [HI]² = (mol.dm¯³)² = No units.
[H₂][I₂] (mol.dm¯³)(mol.dm¯³)
Q23: What will be the units of Kᴄ in following reactions?
N₂ + 3H₂ 2NH₃
Ans:
Kc = [NH₃]² = (mol.dm¯³)² = 1 = mol¯²dm⁶
[N₂][H₂]³ (mol.dm¯³)(mol.dm¯³)³ (mol.dm¯³)²
Q24: How can we write equilibrium constant expression for a reaction?
Ans: It is conventional to write product side in numerator and reactants as denominator.
Example: N₂ + O₂ 2NO
Kc = [NO]²
[N₂][O₂]
Q25: Difference Between Forward and Reverse Reaction?
Ans:
Forward Reaction Reverse Reaction
(i) In which reactant react to form
products.
In which product react to form
reactant.
(ii) It takes place from left to right. It takes place from right to left.
(iii) It slows down gradually. It speedup gradually.
Q26: Who gave law of Mass action?
Ans: Guldberg and waage in 1869 put forward law of mass action.
Q27: Name a factor on which Kᴄ depends?
Ans: The value of Kᴄ depends only on temperature. It does not depend upon initial
concentration of reactants and products.
Q28: What are the major Components of atmosphere?
Ans: Nitrogen and Oxygen are the major components of atmosphere.
Kc
Small
Qc
Large

Q29: Give the Importance of Nitrogen in Industry?
Ans: It is used to manufacture ammonia which is further used in nitrogenous fertilizer.
Example: Urea
Q30: How is Oxygen important in preparation of Sulphuric acid?
Ans: Oxygen is used to prepare Sulphur dioxide. Sulphur dioxide is used in preparation
of Sulphuric acid (H₂SO₄)
Q31: Name a King of chemical?
Ans: H₂SO₄ is called King of chemicals.
Q32: Derive equilibrium constant expression for ionization of Hydrochloric acid?
Ans: Hydrochloric acid ionizes in aqueous solution as:
HCl H⁺ + Cl¯
Kc = [H⁺][Cl¯]
[HCl]
Q33: Give Kᴄ of following reaction?
N₂ + O₂ 2NO
Ans: Rf = Kf [N₂][O₂] = Rate of forward reaction.
Rf = Kf [NO]² = Rate of reverse reaction.
Kc = [NO]² = Equilibrium constant expression.
[N₂][O₂]
Q34: Define Chemical Reaction?
Ans: When substance (reactants) combines to form new substances (products) it is
called Chemical Reaction. Reaction and Products are separated by arrow ( )
Q35: What are different Types of chemical reactions?
Ans: There are two types of chemical reaction: -
(i) Reversible Reactions. (never complete)
(ii) Irreversible Reactions. (goes to completion)
Q36: What is Haber’s process?
Ans: Ammonia is synthesized by Haber’s process under certain condition of
temperature, pressure and catalyst.
N₂ + 3H₂ 2NH₃
Q37: Why is dynamic equilibrium established in closed vessel?
Ans: Because products formed in reversible reaction will not escape out in closed
vessel.
Q38: Define Kf and Kr?
Ans: Kf is specific rate constant for forward reaction. While Kr is specific rate constant
for reverse reaction.
Q39: Define Reaction quotient?
Ans: Reaction quotient is [Products] = ratio at any moment of reversible reaction. It is
denoted by Qᴄ. [Reactants]
Test Yourself 9.1
Q1: Why reversible reactions never complete?
Ans: Because products recombine to form reactants and reaction occurs in both direction i.e
forward and backward.
Q2: What is static equilibrium, explain with an example.
Ans: When reaction ceases to proceed it is called Static Equilibrium. It occurs in physical
phenomenon.
Example: A building remains standing rather than falling down.
Q3: Why the amounts of reactants and products do not change in reversible reaction.
Ans: It is because of dynamic equilibrium.

Test Yourself 9.2
Q1: Define Law of Mass Action?
Ans: “The rate at which a substance reacts is directly proportional to active mass and the rate
of reaction is directly proportional to the product of the active masses of the reacting
substances”
Q2: How the active mass is represented?
Ans: Active mass is represented in square brackets, as [ ]
Q3: What do you mean by equilibrium constant?
Ans: “Ratio of the product of concentration of products raised to the power of co-efficient to
the product of concentration of reactants raised to the power of co-efficient as expressed in a
balance chemical equation”
Test Yourself 9.3
Q1: What do you mean by the extent of reaction?
Ans: It indicates to which extent reactants are converted into products.
Q2: Why the reversible reactions do not go to completion?
Ans: Because products recombine to form reactants and reaction occurs in both direction i.e
forward and backward. Reaction having small magnitude of Kc represents establishment of
equilibrium state.
Q3: If a reaction has large value of Kc, will it go to completion and why?
Ans: Those reactions that have large Kc value proceed almost forward so; more of the
products are required to attain equilibrium.
Q4: Which types of reactions do not go to completion?
Ans: Reversible Reactions do not go to completion.
Q5: Why the reaction mixture does not have 50% reactants and 50% products at
equilibrium position?
Ans: Because products recombine to form reactants to attain the equilibrium where amount of
reactants and products will remain same and reaction proceed at equal rate.
(Important Long Questions)
1. Define Law of mass of action?
2. Difference between forward and reverse reaction?
3. Define Equilibrium Constant and Active Mass?
4. Difference between Reversible and Irreversible?
5. Define Reactants and Products?
6. Define Static Equilibrium?

M.C.Q’s
Answers
1 B 2 D 3 A 4 C 5 C
6 A 7 D 8 B 9 A 10 C
11 B 12 D 13 D 14 C 15 C
16 D 17 D 18 A 19 D 20 A
Q1: Name three common household substance having:
(a)pH value greater than 7
Ans:
(i) White Wash Ca(OH)₂
(ii) Caustic Soda NaOH
(iii) Milk of Magnesia Mg(OH)₂
(b)pH value less than 7
Ans:
(i) Sour milk Lactic Acid
(ii) Apple Malic Acid
(iii) Lemon Citrus
(c)pH value equal to 7
Ans:
(i) Table salt solution NaCl
(ii) Water H₂O
(iii) Calcium chloride CaCl₂
Q2: Define a Base and explain all alkalis are bases, but all bases are not alkalis?
Ans: A species that release OH¯ in aqueous solution and accept a proton.
Alkali: A soluble base called alkali. It gives hydroxides ions in solutions. So, all
alkalis are bases but all bases not alkalis.
Q3: Define Bronsted-Lowry base and explain with an example that water is a
Bronsted-Lowry base?
Ans: According to Bronsted-Lowry concept: Proton donor species are known as
acids While Protons acceptor species are known as bases.
Example: HCl + H₂O H₃O⁺ + Cl¯
Q4: How can you justify that Bronsted-Lowry concept of acid and base is
applicable to non-aqueous solutions?
Ans: “An acid is a compound which donate a proton (H⁺)”
“A base is a compound which accept a proton (H⁺)”
So, the compounds which have H⁺ ions are also acts as acid in addition to water.
Example: HCl
Acids, Bases &
Salts
CHAPTER
10

The compound which has not OH ions is also act as base. Example: NH₃
Q5: Which kind of bond forms between Lewis acid and a base?
Ans: A coordinate bond is formed between Lewis acid and base. In this type of bond
shared pair of electrons denoted by only one atom to other.
Q6: Why H⁺ ion acts as a Lewis acid?
Ans: H is an electron deficient. It has empty orbital. It completes its valence shell with
two electrons. So, it is electrophiles as:
H H
H + N H H N H
H H
Q7: Name two acids used in the manufacture of fertilizer?
Ans: Nitric Acid (HNO₃) and Sulphuric Acid (H₂SO₄) are used in manufacture of fertilizer.
Q8: Define pH? What is the pH of pure water?
Ans: It is negative logarithm of hydrogen ion. pH = log(H⁺)
Q9: How many times a solution of pH 1 will be stronger than that of a solution
having pH 2?
Ans: A solution of pH 1 has 10 times higher concentration of H⁺ than that of a solution of
pH 2.
Q10: Define the followings:
(a)Normal salt
Ans: A salt formed by total replacement of ionizable H⁺ ions of an acid by a positive
metal ion or NH₄¯ ions.
(b)Basic salt
Ans: A salt formed by incomplete neutralization of poly hydroxyl base by an acid.
Q11: Na₂SO₄ is a neutral salt while NaHSO₄ is an acid salt. Justify?
Ans: Na₂SO₄ is formed by complete replacement of H⁺ ions from an acid. While NaHSO₄
is formed by partial replacement of H⁺ ions of an acid
Example: 2NaOH + H₂SO₄ Na₂SO₄ + H₂O
NaOH + H₂SO₄ NaHSO₄ + H₂O
Q12: Give a few characteristic properties of salts?
Ans:
(i) Salts are found in crystalline form.
(ii) They have high melting and Boiling point.
(iii) These are neutral compounds.
Q13: How are the soluble salts recovered from water?
Ans: First saturated solution is prepared and then filtered it. Filtrate it crystallized by slow
evaporation. So, soluble salts are separated by crystallization method.
Q14: How are the insoluble salts prepared?
Ans: Insoluble salts are prepared by mixing solutions of soluble salts.
Example: AgNO₃ + NaCl AgCl + NaNO₃
Na₂CO₃ + CuSO₄ CuSO₃ + Na₂SO₄
Q15: Why a salt is neutral, explain with an example?
Ans: Because salt is formed by neutralization reaction between acid and base.
Example: NaOH + HCl NaCl + H₂O
Q16: Name an acid used in the preservation of food?
Ans: Benzoic acid (CH₆C₅OOH) and Acetic acid (CH₃COOH)
Q17: Name the acids present in:
(a)Vinegar Ans: Acetic acid (CH₃COOH)
(b)Ant sting Ans: Formic acid (HCOOH)

(c)Citrus Fruit
Ans: H
H―C―COOH
(HO―C―COOH)
H ―C― COOH
(d)Sour milk H
Ans: OH
CH₃―CH
COOH
Q18: How can you justify that Pb(OH)NO₃ is a basic salt?
Ans: Pb (OH)NO₃ has replaceable hydroxide ion which is a indication of basic salt. Thus
hydroxide ion is neutralized by an acid. Such as:
Pb(OH) NO₃ + HNO₃ Pb (NO₃)₂ + H₂O
Q19: You are in a need of an acidic salt. How can you prepare it?
Ans: Acidic salt is prepared by partial neutralization of an acid with a base.
KOH + H₂SO₄ KHSO₄ + H₂O
Q20: Which salt is used to prepare plaster of Paris?
Ans: Calcium sulphate or gypsum (CaSO₄.2H₂O) is used to prepare plaster of Paris.
Test Yourself 10.1
Q1: What is the difference between Arrhenius base and Bronsted-Lowery Base?
Ans: See on book.
Q2: What do you mean by neutralization reaction according to Arrhenius acid-base
concept?
Ans: When both HCl and NaOH are ionized in water neutralization reaction takes place.
Q3: Prove that water is amphoteric specie?
Ans: Water is amphoteric specie because water acts as a base when it reacts with acid while
as an acid when it reacts with base.
Q4: How can you justify that NH3 is Bronsted-Lowry base but not Arrhenius base?
Ans: NH3 can accept a proton but it can’t give (OH-) ion in the aqueous solution that while NH3
acts as Bronsted-Lowry base while it does not act as Arrhenius base.
Q5: State and explain the neutralization reaction according to Lewis concept.
Ans: “Donation and acceptance of an electron pair to form a coordinate covalent bond in
an adduct”
Q6: Define and give the characteristics of Lewis Acid?
Ans: Definition: “An Lewis acid is a substance which can accept a pair of electron”
Characteristics:
o These are the molecules in which the central atom has incomplete octet.
o Simple cations can act as Lewis acids.
Q7: Why BF3 behaves as Lewis Acid?
Ans: BF3 is an electron deficient compound, it has incomplete octet. So, it can accept a pair of
electron to form a adduct.

Test Yourself 10.2
Q1: When acids react with carbonates and bicarbonates, which gas evolves out?
Ans: When acids react with carbonates and bicarbonates carbon dioxide gas is evolved.
Q2: Which types of salts produce SO2 gas on reacting with acids?
Ans: Sulphites and bisulphites react with acids to produce SO2 gas
Q3: Give the uses of sulphuric acid?
Ans: (a) Sulphuric acid is used to manufacture fertilizers, dyes and drugs.
(b) It is also used as an electrolyte in lead storage batteries.
Q4: Name the gas liberated when alkalies react with ammonium salts.
Ans: When alkalies react with ammonium salts it produce ammonia gas.
Q5: Write down the colours of the precipitates formed by reaction of aqueous caustic
soda with solutions of: Copper, Zinc and Ferric Salts
Ans: Copper salt = Copper hydroxide = Blue ppt
Zinc salt = Zinc hydroxide = White ppt
Ferric salts = Ferric hydroxide = Dirty green
Q6: Name an alkali used in alkaline batteries.
Ans: Potassium hydroxide (KOH) is used in alkaline batteries.
Test Yourself 10.3
Q1: Why pure water is not a strong electrolyte?
Ans: Pure water is not a strong electrolyte because it ionizes very slightly into ions in a
process called auto-ionization.
Q2: HCl and H2SO4 are strong acids. While their solutions are equimolar, they have
different pH value. Why they have different pH values?
Ans: Equimolar of HCl and H2SO4 have different pH values because when HCl ionized it
produce one H+
ion, While H2SO4 is dibasic acid it produce two H+
ions.
Q3: Why ionic-product constant of water is temperature dependent?
Ans: Because ionization increases with the increase in temperature.
Q4: Differentiate between “p” and “pH”.
Ans: pH is negative logarithm of concentration of H+ ion i.e pH = -log[H+] while “p” scale is the
conversion of very small figures into positive figures by taking common logarithm of the small
figure and multiply it with 1.
Test Yourself 10.4
Q1: How the salts are named?
Ans: Name of salt derived from its basic radical and acidic radical.
Q2: Name the salts which are formed when Zn metal reacts with following acids.
(a) Nitric Acid (b) Phosphoric Acid
(c) Acetic Acid
Ans: (a) Zn + Nitric acid Zinc nitrate
(b) Zn + Phosphoric acid Zinc Phosphate
(c) Zn + Acetic Acid Zinc Acetate
Q3: How will you justify salts are neutral compounds?
Ans: Slats are formed by neutralization reaction between acid and base. They have equal
number of positive and negative charges.

Q4: How many water of crystallizations are present in CuSO4.5H2O and CaSO4.2H2O?
Ans: In CuSO4.5H2O there are 5 water molecules while in CaSO4.2H2O are two water of
crystallization.
Q5: Name the type of reaction that takes place between an acid and a metal. Which gas
would evolve in the reaction? Explain with an example.
Ans: These reactions are called direct displacement reactions. Hydrogen gas is evolved
during these types of reactions.
2HCl + Mg MgCl2 + H2
Zn + 2HCl ZnCl2 + H2
Test Yourself 10.5
Q1: Name the types of salts.
Ans: Following are the main types of classes as:
(a) Normal Salts (b) Acidic Salts
(c) Basic Salts (d) Double Salts
(e) Mixed Salts (f) Complex Salts
Q2: H3PO4 is a weak acid but its salts (Na3PO4) with strong base NaOH is neutral.
Explain it.
Ans: H3PO4 + 3NaOH Na3PO4 + 3H2O
Q3: How the basic salts turns into normal salts? Explain with an example.
Ans: Zn(OH)NO3 + HNO3 Zn(NO3)2 + H2O
Q4: What are complex salts?
Ans: Complex salts provide a simple cation and complex anion.
Q5: Na2SO4 is a neutral salt. What are its uses?
Ans: Na2SO4 is used for the manufacture of explosives, plastics and other chemicals.
Q6: What is Acid Rain?
Ans: Acid Rain is formed by dissolving acidic air pollutants like oxides of Sulphur and nitrogen
by rain water.
1. Give two properties of Acids and Base?
2. Difference between Lewis and Conjugate bases?
3. Define PH and Complex Salt?
4. Give two properties of Salts?
5. Write Limitation of Arrhenius Concept?
6. Write Uses of Acids and Bases?
7. Define Salts and give its Uses?

M.C.Q’s
Answers
1 B 2 C 3 A 4 D 5 B
6 C 7 A 8 B 9 A 10 C
11 B 12 A 13 B 14 D 15 B
16 C 17 C 18 C 19 C 20 B
21 A 22 C 23 C
Q1: What is meant by the term Catenation? Give an example of a compound that
displays catenation?
Ans: “The self-linking property of carbon atoms through covalent bonds to form long
straight or branched chains and rings of different sizes is called Catenation”.
Example: CH₃―CH₂―CH₂―CH₂―CH₃
Q2: How coal is formed?
Ans: Coal was formed by the decomposition of dead plants buried under the earth’s
crust some 500 million ago. It is a very slow biochemical process. It takes place in the
absence of air under high pressure and high temperature.
Q3: What is importance of natural gas?
Ans: Importance of Natural Gas:-
(a) It is used as fuel in homes and industry.
(b) It is used as fuel in automobiles.
(c) It is used to make carbon black.
Q4: Justify that organic compounds are used as food?
Ans: The food we eat daily such as milk, eggs, meat etc.
Q5: How alkyl radicals are formed? Explain with examples.
Ans: An alkyl radical is formed by the removal of one hydrogen atom from an alkane
Example: CH₃―CH₂― OR C₂H₅¯
Q6: What is the difference between n-propyl and isopropyl? Explain with
structure.
Ans: n-propyl is formed by the removal of the removal of terminal H atom from either
end of propane. Isopropyl radical is formed by the removal of central H from propane.
CH3 ― CH2 ― CH2 CH3 ― C ― CH3
Q7: Explain different radicals of butane? H
Ans: There are two butanes:-
Organic
Chemistry
CHAPTER
11

CH3
n-Butane
CH3 ― CH2 ― CH2 ― CH3 CH3 ― CH ― CH3
Q8: Define functional group with an example?
Ans: “An atom or a group of atoms or a double or a triple bond whose presence gives
characteristics properties to an organic compound is called a Functional Group”
Example: CH₃―CH₂―OH
Q9: What is an ester group? Write down the formula of ethyl acetate.
Ans:
Ester Group: - ―COO― OR ―C―O―
Formula of ethyl acetate: - CH₃―C―O―CH₂―CH₃
Q10: Write down the dot and cross formula of propane and n-butane?
Ans:
H H H H H H H
H C C C H H C C C C H
H H H H H H H
Q11: Define structural formula? Draw the structural formula of n-butane and
isobutene?
Ans: A formula that shows the arrangement of atoms in a molecule of a compound.
Example: CH₃―CH₂―CH₂―CH₃
Q12: Write classification of coal?
Ans: Coal is classified into four types: -
(a) Peat (b) Lignite (c) Bituminous (d) Anthracite
Q13: What are Heterocyclic Compounds? Give two examples.
Ans: Organic compounds that contain a ring made up of more than one kind of atom are
called Heterocyclic Compounds.
Example:-
Q14: Why benzene and other homologous compounds of benzene are called
Aromatic Compounds?
Ans: The organic compounds contain at least one benzene ring in their molecule are
called Aromatic Compounds.
Example:-
A ring made up of six carbon atoms with three alternate double bonds is called Benzene
Ring.
Example:-

Test Yourself 11.1
Q1: Why and how carbons complete its Octet?
Ans: Carbon gets minimum energy and maximum stability by sharing its four valence
electrons with other atoms.
Q2: Why the melting and boiling points of organic compounds are low?
Ans: Because the intermolecular forces between the organic molecules are weak.
Q3: Why the organic compounds are poor conductors of electricity?
Ans: Because organic compounds consist of molecules having covalent bonds between
atoms.
Test Yourself 11.2
Q1: Name the gases which are found in coal gas?
Ans: The gases which are found in coal gas are hydrogen, methane, carbon monoxide.
Q2: Is coal tar a compound?
Ans: Coal tar is not a compound.
Q3: What is Coke?
Ans: Coke is 98% carbon.
Q4: Which is the best quality of coal?
Ans: The best quality of coal is Anthracite (98% Carbon)
Q5: What is destructive distillation?
Ans: “The strong heating of coal in the absence of air is called destructive distillation”
Test Yourself 11.3
Q1: Define Petroleum?
Ans: “A dark brownish or greenish black coloured viscous liquid is called petroleum”
Q2: What types of compounds are synthesized by plants?
Ans: Living plants synthesize compounds such as carbohydrates, proteins, oils and
vitamins.
Q3: What is the basic unit of carbohydrates and how it is synthesized?
Ans: The basic unit of carbohydrates is glucose.
Q4: CNG stands for……..?
Ans: CNG stands for Compressed Natural Gas.
1. Define Catenation and Isomerism?
2. What is the role of Vital Force Theory and Ester Group?
3. What is the Difference between Molecular and Structural Formula?
4. What is meant by Organic Compound and give its Uses?
5. Difference between Homocyclic and Heterocyclic Compounds?
6. Define Functional Group with Example?
7. Difference between Aromatic and Alicyclic Compounds?

M.C.Q’s
Answers
1 A 2 B 3 A 4 C 5 C
6 C 7 B 8 C 9 D 10 B
11 C 12 B 13 C 14 A 15 B
16 A 17 C 18 C 19 A 20 B
Q1: Differentiate Between Saturated and Unsaturated Hydrocarbons?
Ans:
Saturated Hydrocarbons Unsaturated Hydrocarbons
Hydrocarbons in which two carbon atoms
are linked by a single bond.
Hydrocarbons in which two carbon atoms
are linked by a double or a triple bond.
Example: CH₃―CH₃ Example: CH₂ = CH₂
Q2: A compound consisting of four carbon atoms has a triple bond in it. How
many hydrogen atoms are present in it?
Ans: CH₃― CH₂―C = CH and CH₃―C = C―CH₃
The compound has six hydrogen atoms.
Q3: Why Alkanes are called “Paraffin’s”?
Ans: They are least reactive. That’s why alkanes are called “Paraffin’s”.
Q4: What do you know about Hydrogenation of alkenes?
Ans: “The addition of hydrogen across a double bond is called Hydrogenation”.
Example: CH₂ = CH₂ + H₂ CH₃― CH₃
Q5: How alkyl halides are reduced?
Ans: Alkyl halides are reduced to alkanes with nascent hydrogen which is obtained by
the action of Zn with dilute HCl.
R―X + 2[H] R―H + HX
Q6: Why the Alkanes are used as Fuel?
Ans: Because burning of alkanes in the presence of excess of air or oxygen produces a
lot of heat.
Q7: How can you prepare Ethene from Alcohol and Ethyl bromide?
Ans: (i) CH₃―CH₂―OH + HOSO₃H CH₃―CH₂―OSO₃H + H₂O
CH₃―CH₂―OSO₃H CH₂=CH₂ + H₂SO₄
(ii) CH₃―CH₂―Br + KOH CH₂=CH₂ + KBr + H₂O
Hydrocarbons
CHAPTER
12

Q8: Identify Propene from Propane with a chemical test?
Ans: Propene reacts with cold alkaline KMnO₄ solution to give a colourless 1,2-
propanediol. Propane does not react with KMnO₄.
OH OH
3CH₃―CH=CH₂ + 2KMnO₄ + 4H₂O 3CH₃―CH ― CH₂ + 2MnO₂ + 2KOH
Q9: Why the alkenes are called olefins?
Ans: Since lower members of alkene form oily products on treatment with Cl₂ or Br₂,
therefore, alkenes are also called olefins.
Q10: Why alkane can’t be oxidized with KMnO₄ solution?
Ans: In alkanes because all the valencies of carbon atoms are fully satisfied by single
bonds. They are saturated. The single bonds are highly strong. Therefore, alkanes
cannot be oxidized with KMnO₄ solution.
Q11: What are the Addition Reactions? Explain with an example?
Ans: “A reaction in which two atoms or groups are attached to each carbon of the double
or triple bond is called Addition Reaction”. Br Br
Example: CH=CH₂ + Br₂ CH₂―CH₂
Q12: Justify that alkanes give substitution reactions?
Ans: Since in alkanes all bonds are single bonds which are very strong. Therefore,
alkanes give only substitution reactions.
Q13: Both, Alkenes and Alkynes are Unsaturated Hydrocarbons. State the one
most Significant Difference between them?
Ans: The difference is that alkynes are capable of adding two molecules of the reagent
while alkenes are capable of a adding only one molecule of the reagent.
Q14: Write the molecular, dot and cross and structural of ethyne?
Ans: Molecular formula of ethyne: C₂H₂
Structural formula of ethyne: H―C = C―H
Dot and Cross formula of ethyne: H C : : C H
Q15: Why Hydrocarbons are soluble in Organic solvent?
Ans: Like dissolves like, therefore, hydrocarbons being non-polar in character are more
soluble in non-polar organic solvents such as ether, carbon tetra chloride, etc. These are
insoluble in water and other polar solvents.
Q16: Give the Physical Properties of Alkanes?
Ans: Physical Properties of Alkanes:
(i) First four members are gases, C₅ to C₁₇ are liquids while higher
members of alkanes are solids.
(ii) They are non-polar and are soluble in non-polar organic solvents.
(iii) The density of alkanes increases gradually with the increase of
molecular mass.
(iv) The melting and Boiling points of alkanes increase with the increase
of molecular size.
Q17: How can you identify Ethene from Ethane?
Ans: Ethene decolourize the pink colour of cold, dilute, alkaline solution of potassium
permanganate due to formation of colourless 1,2-ethanediol.

OH OH
3CH₂=CH₂ + 2KMnO₄ + 4H₂O 3CH₂―CH₂ + 2MnO₂ + 2KOH
Q18: Why Colour of Bromine water discharges on addition of Ethane in it?
Ans: The reddish brown colour of bromine water discharges on a addition of ethene in it
due to formation of colourless 1,2-dibromoethane.
Br Br
CH₂=CH₂ + Br₂ CH₂―CH₂
Q19: State One Important Use of each:
Ans: (i) Ethene
Ethene is used for manufacturing of polythene plastic.
(ii) Acetylene
Acetylene is used in Welding and Cutting of metals.
(iii) Chloroform
Chloroform is used for general anaesthesia.
(iv) Carbon tetra chloride
Carbon tetrachloride is used as an industrial solvent.
Test Yourself 12.1
Q1: Why hydrocarbons are considered as parent organic compounds?
Ans: Because other organic compounds, are derived from them by replacing one or more
hydrogen atoms by other atoms or group of atoms.
Test Yourself 12.2
Q1: Which is the simplest alkane?
Ans: The simplest alkane is methane, CH4
Q2: Why the burning of alkanes require sufficient supply of oxygen?
Ans: The complete burning of alkanes requires sufficient supply of oxygen to form CO2,
H2O and heat.
Q3: What do you mean by halogenation?
Ans: “A substitution reaction in which one or more hydrogen atoms of an alkane are replaced
by halogens atoms is called halogenation”
Test Yourself 12.3
Q1: Why alkenes are reactive?
Ans: Because of electrons of the double bond are easily available for reaction.
Q2: Give few uses of ethane?
Ans: Uses of ethane:
o It is used for artificial ripening of fruits.
o It is used as a general anesthetic.
o It is used for preparing “mustard gas”
Test Yourself 12.4
Q1: Why the alkynes are called acetylenes?
Ans: The name of the first member of this series is acetylene, therefore the common name for
this series is acetylene.

Q2: What is the difference between glycol and glyoxal?
Ans: Glycol:
“A class of compounds containing two hydroxyl groups attached with the
adjacent carbon atoms is called glycol”
Glyoxal:
“A compounding having two aldehydic groups is called glyoxal”
Q3: Write the formula of oxalic acid?
Ans: The formula of oxalic acid:
COOH
COOH
1. Why Alkanes are called “Paraffins”?
2. Define Alkanes and Hydrogenation?
3. Difference between Saturated and Unsaturated Hydrocarbons?
4. Give two Physical Properties and Sources of Alkane?
5. Why Alkenes are called “Oleffins”?
6. Write the equation of Combustion and Halogenation?
7. Give two physical Properties of Alkene and Alkyne?
8. Write two uses of Alkene and Alkyne?
9. Difference between Open chain and Closed chain?

M.C.Q’s
Answers
1 C 2 C 3 D 4 A 5 C
6 C 7 B 8 C 9 B 10 B
11 D 12 C 13 D 14 A 15 A
16 A 17 B 18 C 19 B 20 D
Q1: How Plants Synthesize Carbohydrates?
Ans: Carbohydrates are synthesized by plants through photosynthesis process from CO₂
and H2O in the presence of sunlight and green pigment chlorophyll.
6CO2 + 6H2O C6H12O6
Q2: Give the Characteristics of Monosaccharides?
Ans: Characteristics of Monosaccharides:
(i) Monosaccharides are white crystalline solids.
(ii) They are soluble in water.
(iii) They have sweet taste.
(iv) They cannot be hydrolyzed.
Q3: What is Difference Between Glucose and Fructose?
Ans: Glucose is a pentahydroxy aldehyde while fructose is pentahydroxy ketone having
an open chain structure.
CHO OH
CH2
H ― C ― OH C = O
HO ― C ― H HO ― C ― H
H ― C ― OH H ―C ― OH
H ― C ― OH H ―C ― OH
CH2OH CH2 ―OH
Q4: Give an Example of Disaccharide. How it is hydrolyzed into
Monosaccharides?
Ans: Sucrose is an example of a disaccharide which on hydrolysis produces one
molecule of glucose and one molecule of fructose.
C12H22O11 + H2O C6H12O6 + C6H12O6
Biochemistry
CHAPTER
13

Q5: Give the Characteristics of Polysaccharides?
Ans: Characteristics of Polysaccharides:
(i) Polysaccharides are amorphous solids
(ii) They are insoluble in water
(iii) They are tasteless
(iv) They are non-reducing compounds
Q6: Where the Proteins are found?
Ans: Proteins make up more than 50% of the dry weight of animals.
Q7: Describe the Uses of Carbohydrates?
Ans: Uses of Carbohydrates:
(i) They regulate the amount of sugar level in our body.
(ii) Dietary fiber helps to keep the bowel functioning property
(iii) Fiber helps in lowering of cholesterol level and regulates
blood pressure
(iv) They protect our muscles from cramping
Q8: Lactose is disaccharide, which monosaccharides are presentation it?
Ans: In lactose, the monosaccharides glucose and galactose are present.
C12H22O11 + H2O C6H12O6 + C6H12O6
Q9: Why the Ten Amino Acids are essential for us?
Ans: Because human body cannot synthesize essential amino acids.
Q10: How Proteins are found?
Ans: Two Amino acids link through peptide linkage. Peptide linkage is formed by the
elimination of water molecule between the amino group of one amino acid and carboxyl
group of another amino acid.
Example:
R O R O R O R O
H2N ― CH― C ―OH + HNH ― CH ― C ― OH H2N ― CH― C ― NH ― CH ― C
― OH
Q11: How Gelatin is Obtained?
Ans: Proteins are found in bones. Gelatin is obtained on heating bones.
Q12: Give the General Formula of the Lipids?
Ans: General Formula of Lipids is Triglyceride.
O
CH2 ― O ― C ― R
O
CH2 ― O ― C ― R
O
CH2 ― O ― C ― R
Q13: Name Two Fatty Acids with their Formula?
Ans: (a) Palmitic acid [C15H31COOH] (b) Stearic acid [C17H35COOH]
Q14: Give the Types of Vitamins?
Ans: Vitamins are Two types: - (a) Fat soluble vitamins (b) Water soluble
vitamins

Q15: What is the Significance of Vitamins?
Ans: Human body is unable to synthesize vitamins. So, they must be supplied through
diet, vitamins are absolutely necessary for our normal growth. They help to regulate our
body’s metabolism.
Q16: Describe the Sources and Uses of Vitamins A?
Ans: Sources: Dairy products, egg, oil and fats, fish, beta carotene found in green
vegetables, carrots and liver.
Uses: It plays an important role in bone growth, tooth development, reproduction,
cell division and gene expression.
Q17: Deficiency of Vitamins K leads to which Disease?
Ans: Vitamins K play an essential role in normal blood clotting. Its deficiency causes
delay in blood clotting.
Q18: Justify Water soluble Vitamins are not Injurious to Health?
Ans: This is because water soluble vitamins are rapidly excreted from the body. Hence,
they are not toxic even if taken in large quantity.
Q19: What do you mean by Genetic Code of Life?
Ans: DNA is the permanent storage place for genetic information in the nucleus of a cell.
It carries and stores all genetic information of the cell. It passes this information as
instructions from generation to generation how to synthesize particular proteins from
amino acids. These instructions are “Genetic Code of Life”.
Q20: What is the Function of DNA?
Ans: DNA carries and stores all genetic information of the cell. It passes this information
as instructions from generation to generation.
Q21: How you justify RNA works like a Messenger?
Ans: RNA consists of ribose sugar. It is a single stranded molecule. It is responsible for
putting the genetic information to work in the cell build proteins.
Test Yourself 13.1
Q1: Define Carbohydrates?
Ans: “Polyhydroxy aldehydes or ketones, or substances which produce such compounds on
hydrolysis are called carbohydrates”
Q2: Give the characteristics of disaccharides.
Ans: Characteristics of Disaccharides:
1. They are white crystalline solids.
2. They are easily soluble in water.
3. They have sweet taste.
Test Yourself 13.2
Q1: Which elements are found in proteins?
Ans: The elements found in proteins are: carbon, hydrogen, oxygen, nitrogen and Sulphur.
Q2: Give the general formula of amino acid?
Ans: The general formula of amino acid is:
O
R – CH – C – OH
NH3

Q3: What do you mean by non-essential amino acids?
Ans: “Ten amino acids which human body can be synthesized are called non-essential amino
acids”
Test Yourself 13.3
Q1: What is difference between ghee and oil?
Ans: Ghee contains a greater proportion of saturated fatty acids, whereas oil contains a
greater percentage of unsaturated fatty acids.
Q2: Give the characteristics of fats?
Ans: Characteristics of fats:
1. They are insoluble in water.
2. They are lighter than water.
3. Fats in the pure state are colorless and odorless.
4. They are poor conductors of heat and electricity.
Q3: Give the sources and uses of animal fats?
Ans: Animals fats are found in adipose tissue cells. Butter and ghee are used for cooking and
frying of food.
Q4: Plants are sources of oils, justify?
Ans: Plants synthesize oils and store them in seeds such as sun flower oil, coconut oil,
groundnut oil and corn oil.
Test Yourself 13.4
Q1: What are the disadvantages of fat soluble vitamins?
Ans: If fat soluble vitamins are taken in large quantity, they accumulate in the body and cause
diseases.
Q2: What are advantages of water soluble vitamins?
Ans: Water soluble vitamins are rapidly excreted from the body. Hence, these vitamins are not
toxic even if taken in large quantity.
Q3: Give examples of fat soluble vitamins?
Ans: The fat soluble vitamins are vitamin A, D, E and K.
1. Define Oligosaccharides and Monosaccharides?
2. What is meant by Vitamins and Lipids?
3. Write the structure of DNA and Fatty Acids?
4. What is Difference between Glucose and Fructose?
5. Give properties of Polysaccharides?
6. Define Carbohydrates and give two uses of Carbohydrates?
7. What are the Types of Vitamins?
8. What is the Difference between Oil and Ghee?
9. Define Genetic Code of Life and Proteins?
10. Define Amino Acids with their Formula?

M.C.Q’s
Answers
1 A 2 D 3 D 4 A 5 B
6 B 7 B 8 C 9 D 10 B
11 A 12 B 13 A 14 A 15 D
16 B 17 B 18 B 19 A 20 C
Q1: What is the importance of earth for our existence?
Ans: There are four natural systems present on earth which are: -
(i) Lithosphere.
(ii) Hydrosphere.
(iii) Atmosphere.
(iv) Biosphere.
Q2: Define Atmosphere? Name different layers of atmosphere
Ans: “Atmosphere is the envelop of gases around the earth”. It is divided into four
layers: -
(i) Troposphere.
(ii) Stratosphere.
(iii) Mesosphere.
(iv) Thermosphere.
Q3: What is the composition of atmosphere?
Ans: Percentage composition of atmosphere by volume is shown as: -
Nitrogen 78.09 %
Oxygen 20.94 %
Argon 0.93 %
Carbon dioxide 0.03 %
Q4: Why do we study Atmosphere?
Ans: The study of composition of atmosphere provides us the knowledge about the
significance of gases present in the atmosphere.
Q5: Pressure is decreasing gradually in atmosphere. Justify?
Ans: The concentration of the component gases of atmosphere decreases gradually
which results in gradual decrease of pressure.
Q6: What are the characteristics of region of atmosphere?
Ans:
The Atmosphere
CHAPTER
14

Name of region Height above the Earth’s Temperature range and
trend
Troposphere 0 ― 12 km 17 ℃ ― -58℃ (decreases)
Stratosphere 12 ― 50 km -58 ℃ ― 2 ℃ (increases)
Mesosphere 50 ― 85 km 2℃ ― -93 ℃ (decreases)
Thermosphere 85 ― 120 km > ― 93 ℃ (increases)
Q7: Explain phenomenon of decreasing temperature in troposphere?
Ans: Concentration of CO2 and water vapors absorb infrared radiation emitted by earth
surface. So, they warm atmosphere as concentration of these gases decreases gradually
with altitude results in decrease in temperature at the rate of 6K per kilometer.
Q8: State major sources of CO and CO2?
Ans: Major sources of CO and CO2 are: -
(i) Volcanic eruption.
(ii) Combustion of fossil fuels.
(iii) Forest fires.
(iv) Burning of wood.
(v) Decomposition of organic matter.
Q9: Why the 75% of the atmospheric mass lies within the troposphere?
Ans: Troposphere is lower most region of atmosphere and extends up to 12 km, it forms
major portion of atmosphere because it contain very large amount of gases.
Q10: How ozone layer is being depleted by chlorofluro carbons?
Ans: Ultraviolet radiations break the Cl ― Cl bond in CFCl3 and generate chlorine free
radicals as:
CFCl3 CFCl2 + Cl
O3 + Cl O2 + Cl
OCl O + Cl
O + O O2
Q11: What is function of Converter?
Ans: Converter used by automobiles convert harmful CO and oxides of Nitrogen to
harmless CO2 and N2 respectively; unburnt hydrocarbons are oxidized to Carbon dioxide
and water while oxides of Nitrogen are reduced to nitrogen.
Q12: Which Gases is life for Plant and Animal?
Ans: CO2 is life gas for plant while O2 is life gas for animals.
Q13: Taj Mahal has Stone Cancer Comments?
Ans: Acidic gases from industrial units contribute to the wearing away of the famous
marble building. Taj Mahal building is deteriorating by acid rain.
Q14: CO2 is responsible for heating up Atmosphere?
Ans: CO2 is greenhouse gas. It absorbs infrared radiations and allows visible light to
pass through. So, it absorbs most of outgoing radiations which result in heating of
atmosphere.
Q15: CO is a hidden enemy? Explain it action.
Ans: It binds with hemoglobin of blood and forms carboxy hemoglobin. So, supply of
oxygen is cut off. If inhaled for longer time it causes breathing difficulties which lead to
death.

Q16: What threats are to human health due to SO2 gas as air pollutant?
Ans: It causes suffocation, irritation and severe respiratory problems to asthmatic
people.
Q17: Which air pollutant is produced in an anaerobic decomposition of Organic
matter?
Ans: CO2 is an air pollutant produced by anaerobic decomposition.
Q18: How acid rain Increases the acidity of soil?
Ans: Number of acids H2SO4, HNO3 and H2CO3 which are main components of acid rain
comes on the surface of earth results in acidity of soil.
Q19: Point out Two series Effects of Ozone Depletion?
Ans: Two Effects of Ozone Depletion:
(i) It causes skin cancer.
(ii) Depletion of ozone layer will increase infections
disease like malaria.
Q20: How Ozone Layer forms in Stratosphere?
Ans: Ozone layer is formed by the reaction of O2 and atomic oxygen.
Q21: Define Incineration?
Ans: Incineration is a waste treatments process that involves the burning of solid waste
at high temperature. The temperature range from 650 to 100 ℃ in incinerators
Q22: What is Importance of Incinerator?
Ans: Incinerator reduces the solid mass of the original waste by 80-85% and converts
waste material into ash, flue gas and heat.
Q23: What is the Disadvantage of Incineration?
Ans: Incineration produces highly poisonous gas and toxic ash.
Q24: Without CO2 life on Earth would have been Impossible. Comment
Ans: CO2 is the life gas for plant. It absorbs infrared radiations emitted by earth. So, life
is not possible without CO2.
Q25: Why there is a smell near photocopier machine?
Ans: Ozone is well known as it is formed from oxygen near photocopier and other source
of static electricity. There we smell ozone near these sources. It is poisonous gas and
formed on hot day in badly polluted areas.
Q26: What is difference between Pollutant and Contaminant?
Ans: Pollutants are those substances which cause pollution while Contaminants are
those substances that make some impure.
Test Yourself 14.1
Q1: What is the difference between atmosphere and environment?
Ans: Atmosphere is a blanket of gases while environment include each and everything that
surround us.
Q2: Name the major constituents of troposphere?
Ans: The major constituents of troposphere are nitrogen and oxygen.
Q3: How the temperature of atmosphere is maintained?
Ans: CO2 and water vapours maintain temperature of atmosphere.

Q4: Where the ozone layer exists?
Ans: Ozone layer exists in stratosphere about 25 to 30 km away from the earth surface.
Test Yourself 14.2
Q1: What do you mean by an air pollutant?
Ans: Harmful substance present in air called air pollutant.
Q2: Name three primary air pollutants?
Ans: Three primary pollutants are:
SO2 = Sulphur dioxide , SO3 = Sulphur trioxide
CO2 = Carbon dioxide
Q3: Why CO2 is called a greenhouse gas?
Ans: CO2 acts like a glass walls of green house.
Q4: Why the flood risks are increasing?
Ans: Because global warming melts glaciers and snow caps that are increasing flood risk.
Q5: Comment: burning in open air is preferred?
Ans: Because in open air burning produces CO2 gas which becomes part of atmosphere.
Test Yourself 14.3
Q1: How acid rain is produced?
Ans: When rain water mixed with SO2 and NO2 it forms acid rain.
Q2: Why acid rain damages buildings?
Ans: Acid rain attacks the calcium carbonate present in marble and lime stone of boiling.
Q3: How aquatic life is affected by acid rain?
Ans: Acid rain increases the acidity of water and metal salts.
Q4: Why plants are drying day by day? Comment.
Ans: Many plants and crops cannot grow in acidic soil so, growth of soil is restarted.
Test Yourself 14.4
Q1: Justify, ozone is beneficial for human kind?
Ans: It protects from ultraviolet radiations.
Q2: Why ozone is depleting in atmosphere?
Ans: Because of release of chloroflurocarbons.
Q3: What do you mean by ozone layer?
Ans: The region in which ozone layer depletes is called ozone hole.
1. State major Sources of CO and CO2?
2. CO is a hidden enemy? Explain.
3. CO2 is responsible for heating up atmosphere. How?
4. How acid rain increases the acidity of soil?
5. Define Atmosphere and give its types?
6. Write effects of Global Warming?
7. Define Ozone and Water Pollution?
8. Why CO is considered a Health hazard?
9. Why there is a smell near Photocopier machine.

M.C.Q’s
Answers
1 D 2 B 3 D 4 A 5 B
6 A 7 D 8 D 9 C 10 D
11 C 12 B 13 D 14 A 15 B
16 B
Q1: How water rises in Plants?
Ans: Water rises in plants by capillary action. This process is vital for the survival of
plants.
Q2: What is the difference Between Soft water and hard water?
Ans:
Soft Water Hard Water
It is that water which produces good
lather with soap.
It is that type of water which does not
produce good lather with soap.
It does not give curd. It gives curds with soap.
Example: It is free from Ca+2
, Mg+2
ions. Example: Hard water contains Ca+2
, Mg+2
ions.
Q3: Which forces are Responsible for dissolving substance in Water?
Ans: Dipole-Dipole forces are responsible for dissolving polar substances in water.
Q4: Why Non-polar Compounds are Insoluble?
Ans: Non-polar compounds have covalent bonds and they do not have polar ends. So,
non-polar bonds are not attracted by water molecule.
Q5: How water dissolve Sugar and Alcohol?
Ans: Sugar and alcohol have polar ends i.e O¯
― H⁺ group. These substances are
soluble in water due to hydrogen bonding.
Q6: How Lime Stone dissolve in Water?
Ans: Limestone (CaCO3) is insoluble in water but small quantity of lime stone is soluble
in water in the presence of CO2. It is shown as:
CaCO3 + CO2 + H2O Ca(HCO3)2
Q7: What is Softening of Water?
Ans: The removal of Mg+2
and Ca2+
ions which are responsible for the hardness is called
Water Softening.
Q8: What are Types of Hardness of Water?
Water
CHAPTER
15

Ans: There are two types of hardness of water:
(a)Temporary hardness (b) Permanent hardness
Q9: What are the Causes of Hardness in Water?
Ans: Dissolved salts of Mg+2
and Ca+2
with Cl-
, SO4
-2
, HCO3
-1
and CO3
2-
causes
hardness in water.
CaCO3 + CO2 + H2O Ca(HCO3)2
Q10: What is Water Pollution?
Ans: Water pollution is a contamination of includes lakes, rivers, oceans and ground
water.
Q11: Describe Chlorination of Water? Give its Importance.
Ans: It is the addition of chlorine solution in water. Chlorine kills bacteria and other
micro-organisms. Chlorine itself does not kill rather it dissociate in water to form
hypochlorous acid and hypochloric acid.
Cl2 + H2O HOCl + Cl-
+ H+
HOCl turns ionize to produce hypochlorite and proton. So,
HOCl H+
+ OCl-
Q12: What are Effects of Temporary of Detergents?
Ans:
(i) Temporary hard water unfit for aquatic life.
(ii) Insoluble calcium and magnesium carbonates reduce the efficiency of engine
and boiler burst up.
Q13: Mention Disadvantages of Detergents?
Ans:
(i) It makes water unfit for aquatic life.
(ii) They cause diseases by microbes.
(iii) They phosphates salts present in detergents cause rapid growth of algae.
Q14: What is difference between biodegradable and non-biodegradable
substances?
Ans: Those substances that can be decomposed by micro organism like bacteria are
called biodegradable substances and that substance that cannot be decomposed by ion
is or organisms like bacteria are called non-biodegradable.
Q15: How the detergents make the water unfit for aquatic life.
Ans: Phosphate salts present in detergents cause rapid growth of algae. The plants die
and decay.
Q16: Why pesticides are used?
Ans: Because they kill or control the growth of pests. Pests may be weeds, herbs, fungi
and viruses.
Q17: What are the reasons of water borne diseases?
Ans: Diseases that spread because of drinking polluted water or eating food prepared
with polluted water are called water born infectious diseases.
Q18: How water borne disease can be prevented?
Ans: Water borne diseases can be prevented by following measures: -
(i) Provision of safe water.
(ii) Disposal of sewage.
(iii) Control of toxic chemicals.

Q19: Define Soap? How can hard water reduce efficiency of soap?
Ans: “Soap is the sodium salt of long chain carboxylic acids”. Example: Fatty acids.
Calcium and magnesium ions of hard water react with soap to form insoluble
precipitates of calcium and magnesium salts of fatty acid called scum. So, large amount
of soap is washed in scum formation. Thus it decreases the efficiency of soap.
Test Yourself 15.1
Q1: What is capillary action?
Ans: Capillary action is the process by which water rises up from the roots of plants to leaves.
Q2: Why the water molecule is polar?
Ans: Because water has polar bonds which are due to difference of electronegativity between
oxygen and hydrogen atoms.
Q3: Explain why non-ionic polar compounds are soluble in water?
Ans: Because due to hydrogen bonding.
Test Yourself 15.2
Q1: How sodium zeolite softens water?
Ans: Sodium zeolite removes calcium and magnesium ions of hard water. So, makes it soft.
Test Yourself 15.3
Q1: What is an industrial waste?
Ans: A waste particle which is discharged by industrial units is called industrial waste.
Q2: Why use of detergents is increasing day by day?
Ans: Because detergents have strong cleaning action than soap.
Q3: What is function of fertilizers?
Ans: Fertilizers are used to make up the deficiency of nitrogen phosphorous of soil.
Q4: Which of the bacteria causes the cholera?
Ans: Vibrous Cholera.
Q5: What is hepatitis?
Ans: It is a liver inflammation caused by one of five viruses called Hepatitis. A, B, C, D and E.
1. What is the Difference between Hard and Soft Water?
2. What are the effects of temporary hardness?
3. Why pesticides are used?
4. How water borne disease can be prevented?
5. What are the reasons of water borne disease?
6. Define Scum and Dysentery?
7. Write two methods for removal of temporary hardness?
8. Write the Properties of Water?

M.C.Q’s
Answers
1 B 2 C 3 C 4 C 5 C
6 A 7 C 8 A 9 D 10 C
11 A 12 A 13 C 14 C 15 B
16 C
Q1: What role is played by pine oil in the Concentration Process?
Ans: The ore particles are preferentially wetted by oil and the gangue particles by the
water. The whole mixture is agitated with compressed air. “Froth flotation process is
based on the wetting characteristics of the ore and the gangue particles with oil and
water, respectively”.
Q2: Name the Various Metallurgical Steps?
Ans: The Various metallurgical steps are:
(i) Concentration of the ore.
(ii) Extraction of the metal.
(iii) Refining of the metal.
Q3: How Roasting is carried out?
Ans: The process of heating concentrated ore to high temperature in excess of air.
Following reaction: -
2CuFeS2 Cu2S + 2FeS + SO
Q4: Explain Process of Electro Refining?
Ans: “Refining the impure metal by electrolysis is the most widely used process of
refining metals.”
Example: Electrolytic refining of copper is carried out in an electrolytic tank having
copper sulphate solution in it.
Q5: What is Advantages of Solvay’s Process?
Ans:
(i) It is cheap process as raw materials are available at very low price.
(ii) Carbon dioxide and ammonia are recovered and reused.
(iii) Sodium carbonate of very high purity is obtained.
(iv) Consumption of fuel is very less since no solution is to be evaporated.
Q6: What is the Principle of Solvay’s Process?
Ans: Principle of solvay’s process lies in the low solubility of sodium bicarbonate at low
temperature.
Chemical
Industries
CHAPTER
16

Q7: What happens when Ammonical brine is Carbonated?
Ans: Ammonical brine is fed into carbonating tower and carbon dioxide is passed
through it. Following reactants take place in the carbonating tower.
CO2 + NH3 + H2O NH4HCO3
NH4HCO3 + NaCl NaHCO3 + NH4Cl
CO2 + NH3 +H2O + NaCl NaHCO3 + NH4Cl
Q8: How NaHCO3 is Converted to Na2CO3?
Ans: Sodium bi carbonate is heated to get sodium carbonate.
2NaHCO3 Na2CO3 + CO2 + H2O
Q9: How ammonia is recovered in the Solvay’s process?
Ans: Ammonia is recovered in Ammonia recovery tower from ammonium chloride
solution and calcium hydroxide formed in lime kiln.
2NH4Cl + Ca(OH)2 2NH3 + CaCl2 + 2H2O
Q10: How ammonia is prepared for the synthesis of Urea?
Ans: Ammonia is prepared by the “Haber’s Process”.
N2 + 3H2 2NH3
Q11: Describe the Formation of Petroleum?
Ans: Petroleum was formed by the decomposition of dead plants and animals buried
under earth’s crust millions of years ago. It is believed that millions of years ago living
plants and animals in the seas died. Their bodies sank and buried under mud and sand.
Then decomposition process took in the absence of air. Because of high pressure,
temperature and bacterial effects remains of dead plants and animals were converted
into a dark brownish viscous crude oil.
Q12: What is Refining of Petroleum and how it is carried out?
Ans: “Separation of crude oil mixture into various useful products”. It is carried out by a
process called fractional distillation. The principal of fractional distillation is based upon
separation of substance depending upon their boiling point.
Q13: Give a Use of Kerosene Oil?
Ans: It is used as domestic fuel and a special grade of it is used as jet fuel.
Q14: Describe the difference between Diesel oil and Fuel oil?
Ans:
Name Composition Boiling Range
Diesel Oil C13 to C15 250 to 350 C
Fuel Oil C15 to C18 350 to 400 C
Q15: Write down the names of four fractions obtained by the fractional distillation
of residual oil?
Ans: The four fractions of residual oil are: -
(i) Lubricants (ii) Paraffin wax
(iii) asphalt (iv) Petroleum coke
Q16: Which Petroleum Fraction is used in dry cleaning?
Ans: Petroleum Ether is used in dry cleaning. It is composed of C5 to C7
Q17: What is Difference between Crude oil and Residual oil?
Ans: “The oil which does not vapourize is collected and heated above 400 ℃ called
Residual oil”.
“The remains of dead plants and animals were converted into dark, brownish
viscous liquid called Crude oil”.

(Important Short Questions)
Q18: Define Metallurgy?
Ans: The process of extraction of metals in a pure state on a large scale from its ores by
physical or chemical mean is called metallurgy.
Q19: Define Gravity Separation?
Ans: Gravity separation is based on the different in densities of the metallic ore and the
gangue particles.
Q20: What is the difference between mineral and ore?
Ans: The solid natural materials founds beneath the earth’s surface which contains
compounds of metals in the combined state along with earthly impurities are called
minerals.
Those minerals from which the metals are contracted commercially at a
comparatively low cost the with minimum effort we called ores of the metals.
Q21: What is the difference between gangue and slag?
Ans: “The earthly and other impurities associated with the minerals are known as
gangue”
Example: Sulphur, Phosphorous, Manganese, Silicon etc.
“It is the mixture of metal silicates and phosphates”
Example: CaSiO3
Q22: Why hair has different colours?
Ans: The colour of hair is caused by the presence of transition metal compounds in the
hair.
Q23: Why is there a need of phosphorous and nitrogen to crops?
Ans: Crops need phosphorous and nitrogen to grow well.
Q24: What is difference between diesel fuel of summer and winter season?
Ans: Because diesel sets rather like Vaseline at a little below 0C and will not work as a
fuel. More of the lighter fractions are added in winter to prevent this.
Test Yourself 16.1
Q1: Define concentration process used in metallurgy of copper.
Ans: The process of removal of gangue from the ore is technically known as concentration. It
involves following steps:
(a) Gravity Separation (b) Froth Floatation Process
(c) Electromagnetic Separation
Q2: Why a small amount of coke is required in the smelting process?
Ans: It is exothermic process. So, coke is required. It initiates the reaction.
Q3: Why lime is added in the smelting process?
Ans: Lime (CaO) is used to separate the gangue in the form of slag.
Q4: How slag and matte are removed from the blast furnace?
Ans: It reacts with sand and forms slag which float on the top.
2FeS + 3O2 2FeO + 2SO2
FeO + SiO2 FeSiO3
Q5: What is difference between slag and matte?
Ans: Slag is mixtures of metal silicates and phosphates while cuprous sulphide and ferrous
sulphide from a mixture (Cu2S.FeS). This molten mixture is called matte.
Q6: Mention the chemical reaction for the formation of metallic copper in the
bessemerization process.
Ans: 2Cu2S + 3O2 2Cu2O + 2SO2
2Cu2S + Cu2S 6Cu + SO2

Q7: What is blister copper?
Ans: The dissolved gases escape out forming blisters on the surface of solid copper. It is so
called blistered copper.
Q8: Why anode is eaten up in electro-refining process?
Ans: Anode dissolves to give Cu+2 ions to the solution. The Cu+2 ions are discharged by
gaining of electrons from the cathode.
Cu Cu+2 + 2e
Q9: What do you mean by anode mud?
Ans: The impurities like gold and silver settles down as mud.
Test Yourself 16.2
Q1: Why only NaHCO3 precipitates, when CO2 is passed through the ammonical brine?
Ans: NaHCO3 is nearly insoluble in the solution of NH4Cl at 15℃.
Q2: Which raw materials are required for the formation of sodium carbonate?
Ans: Raw materials are NaCl (Sodium Chloride) and NH3 (Ammonia)
Q3: How CO2 is prepared in the Solvay’s process?
Ans: It is formed by heating calcium carbonate.
CaCO3 CaO + CO2
Q4: Give the reaction of formation of ammonia in the process.
Ans: It prepared by mixing one volume of N2 and three volumes of H2 in the presence of ion
catalyst at 450 ℃ and 200 atm.
Q5: Give the advantages of Solvay’s Process?
Ans: (a) It is cheap process. (b) It is pollution free process
Test Yourself 16.3
Q1: What happens when ammonium carbonate is heated with steam?
Ans: It dehydrates to form urea.
Q2: How many stages are involved in the formation of urea?
Ans: Three shapes which are:
(a) Formation of ammonium carbonate
(b) Formation of urea
(c) Granule formation
Q3: What is the percentage of nitrogen in urea?
Ans: The percentage of nitrogen is 46.6%
Test Yourself 16.4
Q1: Define Petroleum?
Ans: Petroleum is a complex mixture of hydrocarbons. It is formed by decomposition of dead
animals and plants buried under the earth’s crust.
Q2: How Petroleum is extracted?
Ans: By drilling holes into earth crust where the oil is found.
Q3: What is principal of fractional distillation?
Ans: The principle of fractional distillation depends upon their boiling points.
Q4: In how many fractions crude oil is separated?
Ans: Six-hydrocarbon fractions are obtained by crude oil.

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