F.Sc. Part 2. Chemistry -inorganic Chemistry portion Board Papers Questions & Solved (Malik Xufyan)

1. Malik Xufyan
Cell # 0313-7355727
Chap no 1
1. Explain why d and f block elements are called transition elements? (fsd 2008, D.G
Khan 2013,)
d and f-block elements are in b/w s and p-block elements. The properties of d and f-block
elements lie b/w s and p-block elements and vary from left to right. It means that their
properties show a transition, so they are called transition elements. Transition elements are
defined as those elements which have partially filled d or f-orbital.
2. The oxidation state varies in a period but remain almost constant in a group. Give
reason. (fsd 2008, lhr 2014, D.G Khan 2012,)
Oxidation states of elements depend upon the electronic configuration of elements. In periods
of periodic table, the electronic configuration change but in a group electronic configuration
remains constant.
Due to same electronic configuration in a group, the elements of the same group have same
oxidation states and due to different electronic configuration in a period, the elements of the
same period have different oxidation states.
3. What are covalent halides? Give two examples. (fsd 2010,
Covalent halides:
 In covalent halides, weak intermolecular forces are present.
 These are generally present as gases, liquids or low melting solids.
 Physical properties of covalent halides depend upon the size and polarizability of halogen
atom.
4. Why diamond is non conductor. Why graphite is fairly a good conductor? (fsd 2010,
14, lhr 2013,
In diamond, C in the form of diamond is non-conductor. It is because all its valance electrons
are used up in making tetrahedral structure and no free electron is present in it.
But C in the form of graphite is a good conductor. It is because it has free valance electrons.
5. Give the general trend of electron affinity in periodic table. (fsd 2011, lhr 2013,
Along period:
Electron affinity increases from left to right in the periodic table due to increase in atomic
size and increase in attraction between the nucleus and valance electrons.
Along group:
Electron affinity decreases from up to down in the periodic table due to increase in atomic
size of elements.
6. What is lanthanide contraction? (fsd 2011, D.G Khan 2009, 11,
Lanthanides are present in 6th
period and actinides are present in 7th
period of periodic table.
In case of lanthanide and actinide, there is a gradual decrease in the atomic size from left to
right due to increase in the nuclear charge. The gradual reduction of atomic sizes in
lanthanide or actinides is called Lanthanide contraction.
7. Justify that BeO is and amphoteric oxide. (fsd 2011,
BeO is an amphoteric oxide. Because it shows the properties of both acidic and basic oxide.

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Cell # 0313-7355727
8. Why is oxidation state of noble gases usually zero? (fsd 2012, lhr 2013,
Oxidation state of noble gases is usually zero. It is because no vacancy is present in their
valance shell. No electron will be added in the noble gases. All the shells in noble gas
completed. Therefore, noble gases are also called zero group elements.
9. Why is metallic character increase down the group of s-block elements? (fsd 2012,
lhr 2014, 15, D.G Khan 2008, 13,
Metallic character increases from top to bottom due to increase in atomic size.
e.g.,
Similarly the metallic character of s-block increases from top to bottom in groups.
In groups, size of atoms increases from top to bottom due to increase in number of shells.
Therefore, metallic character increases down the group of s-block elements.
10. Prove with the chemical reaction that ZnO is an amphoteric oxide. ( fsd 2013, lhr
2013, D.G Khan 2009, 12,
ZnO behaves as amphoteric oxide because it acts as an acid towards bases and as a base
towards strong acids.
For example:
With base:
ZnO + 2NaOH + H2O Na2[Zn(OH)4]
With acid:
ZnO + H2SO4 ZnSO4 + H2O
11. What is hydration energy? How it is varied in the groups and along the periods. (fsd
2013,
Hydration energy is the amount of heat evolved or absorbed when 1 mole of ions dissolve in
water to give infinite solution.
For example:
When one mole of gaseous hydrogen ions are dissolved in water, 1075 kJ energy is released.
H+
(g) + H2O H3O+
(aq)
∆Hh = - 1075 kJmol-1
Along group:
Due to increase in size of elements and decrease in attraction between valance electrons and
nucleus from top to bottom, hydration energy is decreased.
Along periods:
Due to decrease in small size and increase in attraction between valance electrons and
nucleus attraction from left to right, hydration energy is increased.
12. Na2O is basic while P2O5 is acidic in character. Justify. (fsd 2014,
Although both Na and P are present in the same period of periodic table but sodium is metal
while phosphorous is a non-metal. Metal forms basic oxides while non-metals form acidic
oxides. Since sodium is a metal, it will form basic oxide. i.e., Na2O. When this oxide is
dissolved in water, it forms NaOH, that is a base and solution becomes basic.

3. Malik Xufyan
Cell # 0313-7355727
Na2O + H2O 2NaOH
Phosphorous is a non-metal so it will form acidic oxide i.e. P2O5. When this oxide is
dissolved in water, it produces H3PO4, which is an acid, and solution becomes acidic due to
formation of H3PO4.
P2O5 + 3H2O 2H3PO4
13. How melting and boiling points varied in a period? (fsd 2015,
In short periods, melting points increases up to middle with the increase in valance
electrons and then decreases up to noble gases.
 Group IA elements have lowest melting points because they provide one electron per
atom for binding.
 Group IIA elements have slightly higher melting points because they provide two
electrons for binding.
 Carbon provides maximum number of binding electrons. Thus, it has highest melting
point.
 Melting point decreases from group IVA to noble gases. It is because members of the last
groups, exist as single, small covalent molecules. These have weak intermolecular forces.
Thus, their melting points are low.
14. Why the ionic radii of negative ions are larger than size of their atoms. (fsd 2015,
Lhr 2008,
Ionic radii of negative ions are larger due to increase in number of electrons in valance shell.
The size of parent atom is decreased, it is because number of electrons are less in parent atom
than negative ion. When an atom accepts an electron, it takes a negative charge and its size is
increased. Its ionic radius also increased but its positive charge on electron remains same.
15. Why the second value of electron affinity of an element is usually shown with a
positive sign? (Lhr 2008,
When a second electron is added in a un-negative ion, the incoming electron is repelled by
the negative ion and energy is absorbed in the process indicated by the positive figure.
e.g;
O(g) + eˉ Oˉ E.A1 = -141kJmol-1
O(g) + eˉ O2
ˉ E.A2 = +780kJmol-1
16. Why hydrogen can be placed at the top of group 1-Aelements in the periodic table?
(lhr 2009, 10,
Because modern periodic table is in accordance of atomic number. Group I-A elements have
one electron in their valance shell and hydrogen also has one electron in its valance shell.
Therefore, hydrogen is placed in I-A group. Some other similarities such as hydrogen and I-
A group elements have tenancy to give one electron.
17. Why the atomic radius decreases from left to the right within a period and increases
from top to bottom within a group? (lhr 2009,
Along group:
Atomic radius increases down the group due to their two factors.
i) Increase in number of shell ii) Shielding effect

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Cell # 0313-7355727
From up to down number of shell increases and the size of atom is also increased.
Therefore, atomic radius is also increased.
It is the decrease in force of attraction b/w outermost shell and nucleus due to the inner
shell electrons. Shielding effect increases due to increase in size of atom. Therefore,
atomic radius is also increased.
Along period:
Along period atomic radius decrease from left to right. It is because number of shell does
not increase along period. Along period number of electrons increases. Due to this, forces
of attraction between valance electrons and nucleus decrease and size of atom or atomic
radius decreased.
18. What are hydrides? What is the trend of boiling points of hydrides down the group
6-A? (lhr 2010,
Binary compounds of hydrogen with metals are called hydrides.
19. Write name and symbol of an element from S-block that has zero oxidation state
.also write its electronic configuration. (lhr 2011,
Oxidation states of s – block elements is not zero. It may be +1 or +2.
Group I – A
name
Symbols Electronic configuration
Hydrogen H 1s1
Lithium Li 1s2
, 2s1
Sodium Na 1s2
, 2s2
, 2p6
, 3s1
Potassium K 1s2
, 2s2
, 2p6
, 3s2
, 3p6
,4s1
Rubidium Rb 1s2
, 2s2
, 2p6
, 3s2
, 3p6
,4s2
, 3d10
, 4p6
, 5s1
Caesium Cs 1s2
, 2s2
, 2p6
, 3s2
, 3p6
,4s2
, 3d10
, 4p6
, 5s2
, 4d10
, 5p6
, 6s1
Francium Fr 1s2
, 2s2
, 2p6
, 3s2
, 3p6
,4s2
, 3d10
, 4p6
, 5s2
, 4d10
, 5p6
, 6s2
,
4f14
, 5d10
, 6p6
, 7s1
Group II – A
name
Symbols Electronic configuration
Beryllium Be 1s2
, 2s2
Magnesium Mg 1s2
, 2s2
, 2p6
, 3s2
Calcium Ca 1s2
, 2s2
, 2p6
, 3s2
, 3p6
,4s2
Strontium Sr 1s2
, 2s2
, 2p6
, 3s2
, 3p6
,4s2
, 3d10
, 4p6
, 5s2
Barium Ba 1s2
, 2s2
, 2p6
, 3s2
, 3p6
,4s2
, 3d10
, 4p6
, 5s2
, 4d10
, 5p6
, 6s2
Radium Ra 1s2
, 2s2
, 2p6
, 3s2
, 3p6
,4s2
, 3d10
, 4p6
, 5s2
, 4d10
, 5p6
, 6s2
,
4f14
, 5d10
, 6p6
, 7s2
20. Why melting and boiling points of elements belonging to group 5-A to 7-A are
lower? (lhr 2011,
21. The elements of VIII-A group are called noble gasses .comment. (lhr 2011,

5. Malik Xufyan
Cell # 0313-7355727
22. Discuss the trends of ionization energy in periodic table? (lhr 2012, D.G Khan 2010,
13,
Following factors effecting on ionization energy along period;
 From left to right in the periodic table magnitude of nuclear charge increases and I.E is
also increased.
Following factors effecting on ionization energy along group;
 Along group, atomic radii increased and the I.E decreased.
 Greater the shielding effect of inner shell of electrons lower will be the I.E and vice
versa.
23. Give two defects of Mendeleev’s periodic table? (lhr 2012,
Defects of Mendeleev’s periodic table are:
 He arranged the elements in ascending order of their atomic masses.
 Mendeleev placed Be Mg, Ca, Ba and Zn, Cd, Hg in same group. although their
properties are different.
24. Define modern periodic law? (lhr 2014,
The arrangement of elements in a systematic manner, in order to correlate their properties is
called periodic classification. The resulting table is called periodic table.
Modern periodic table is divided into four blocks on the basis of valance shell electronic
configuration. These blocks are:
i) s-block ii) p-block iii) d-block iv) f-block
These blocks tells about the valance shell of electrons of elements and their
properties especially valency and oxidation state.
 s-block elements are the elements in which valance electrons are present in s-orbital.
 p-block elements are the elements in which valance electrons are present in p-orbital.
 d-block elements are the elements in which valance electrons are present in d-orbital.
 f-block elements are the elements in which valance electrons are present in f-orbital.
25. Why do metals conduct electricity? (lhr 2014,
Electrical conductivity is a property of elements that causes the electricity. This property is
due to the free electrons in elements. Free electrons are present in metals. Therefore, metals
are the good conductor of electricity. This property depends upon:
 Presence of loose electrons in valance shell of elements.
 Easy removal of loose electrons.
26. Zn, Cd, Hg was placed with alkaline earth metals in Mendeleev’s table. How this
confusion is removed in the modern periodic table? (lhr 2015,
Zn, Cd, Hg were placed with alkaline earth metals in Mendeleev’s table. This defect was
removed by making another group IIB in a periodic table.

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Cell # 0313-7355727
27. How does hydrogen resemble with alkali metals? Write any four points. (lhr 2015,
Hydrogen resemble with alkali metals by the following ways:
 Like alkali metals hydrogen have only one electron in its outermost s-orbital.
 Like alkali metals, hydrogen can lose its one electron from outermost shell 1s orbit to
form H+
ion.
 Like alkali metals hydrogen ionic compounds of hydrogen ionize in water to give H+
ion.
 Both hydrogen and alkali metals have strong tendency to combine with halogens to
form halides.
28. What are ionic hydrides? Give their properties. (D.G Khan 2009,
Elements of group IA and heavier members of IIA form ionic hydrides. In these hydrides, H
is present as H-
.Their properties are:
 They form basic solution with water.
 These are crystalline solids.
29. Why the elements of subgroup III-A to VIIIA are called P-block elements? (D.G
Khan 2012,
The elements of subgroup III-A to VIII-A are called P-block elements. It is because their
valance shell is P.
30. How does hydrogen resemble with elements of Group IV - A? (D.G Khan 2012, 13,
There are following properties are present in IVA group elements which is similar to
hydrogen atom.
 Valance shell of hydrogen is half filled like group IVA elements.
 Both hydrogen and group IVA members combine with other elements through covalent
bonds.
 Like carbon, hydrogen has strong reducing properties.
e.g. CuO + H2 Cu + H2O
31. Write down any two differences between Hydrogen and alkali metals. (D.G Khan
2013,
Differences between hydrogen and alkali metals are:
 Alkali metals are solid while hydrogen is a gas.
 Hydrogen does not lose its electron as quickly as alkali metals.
Chap no 2
1. Why 2% gypsum is added in the cement? (fsd 2008, lhr 2008, 13, D.G Khan 2011,
12,)
Gypsum prevents the cement from hardening too rapidly. The addition of gypsum increases
the setting time of cement increases interlocking property.
2. Point out the two advantages of Down’s cell. (fsd 2008, 13, D.G Khan 2013, lhr
2013,)
Following advantages are formed;
 The metallic fog is not produced.
 Liquid sodium can be easily collected at 600o
C.

7. Malik Xufyan
Cell # 0313-7355727
 Product form does not react with material of the cell.
3. Discuss the effect of heat on hydroxide of alkali metals. (fsd 2010,
4. Write the chemical reactions when mortar hardens. (fsd 2010,
The chemical reactions when mortar hardens are:
CaO + H2O Ca(OH)2
Ca(OH)2 + CO2 CaCO3 + H2O
Ca(OH)2 + SiO2 CaSiO3 + H2O
5. What is function of calcium in plant growth? (fsd 2012,
The functions of Ca in plant growth are:
i) Ca is essential for the normal growth of plant. Different plants required different
amount of Ca.
ii) Soils containing Ca are alkaline in nature.
iii) Presence of Ca in soil controls the availability of phosphorous in soil.
iv) Ca is also necessary for normal development of leaves. Sufficient Ca accumulates
in leaves and barks.
6. Why is CaCl2 added in molten NaCl in down’s cell. (fsd 2012,
CaCl2 is added in molten NaCl to lower the melting point of NaCl. The melting point of
NaCl is lowered from 801o
C to 600o
C. It is done because at this temperature Down’s cell is
operated.
7. What are main uses of plaster of paris? (fsd 2012,
It is used
 For making plaster walls.
 For casts of statuary, coins etc.
 In surgery. Its bandages are used to keep fractured bone in place after setting.
8. How potassium superoxide (KO2) has a very interesting use in breathing equipment
for mountaineers and in space craft? (fsd 2013, D.G Khan 2012, lhr 2009,
It is because potassium superoxide can absorb carbon dioxide while giving out oxygen at a
same time.
4KO2 + 2CO2 2K2CO3 + 3CO2
9. Write any four points to show peculiar behavior of beryllium. (fsd 2013,
 Be is hard as iron. It is quite hard to scratch glass, while other alkaline earth metals are
softer than Be but still harder than alkali metals.
 Be is more resistant to complete oxidation as compare to its family members, because of
its BeO Coating.
 Melting and boiling points of Be is higher than its family members.

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Cell # 0313-7355727
 Oxides and hydroxides of Be are amphoteric while other alkaline metals form basic
oxides and hydroxides.
10. Why lime water turns milky with CO2 but become clear with excess of CO2? (fsd
2014, 15, lhr 2009, 13, 14, D.G Khan 2013,
Lime water is solution of lime CaO in water. When CaO is dissolved in water, it reacts with
water to produced Ca (OH)2. When CO2 is passed through lime water it reacts with Ca (OH)2
and produced CaCO3.
Ca(OH)2 + CO2 CaCO3 + H2O
The milkyness disappears when excess CO2 is passed through it due to the formation of
Ca(HCO3)2, which is soluble in water.
Ca(OH)2 + CO2 CaCO3 + H2O
CaCO3 + CO2 + H2O Ca(HCO3)2
11. What happen when beryllium reacts with sodium hydroxide and lithium hydride
reacts with water? (fsd 2015,
Lithium hydride with water:
LiH + H2O LiOH + H2
Beryllium with NaOH:
Be + 2NaOH Na2BeO2 + H2
12. Why the alkali metals are strong reducing agents? (lhr 2009,
Alkali metals are strong reducing agents because they give an electron easily. They have only
one electron in their valance shell. They are highly electropositive. They have the capability
to give the electron. For example:
2Na + Cl2 2NaCl
With hydrogen:
At high temperature,
2Li + H2 2LiH
2Na + H2 2NaH
13. Why the aqueous solution of Na2CO3 is alkaline in nature? (lhr 2008, 10, lhr 2011,
15, D.G Khan 2009, 12, 12,
Na2CO3 is hydrolyzed by water to give alkaline solution. In water, Na2CO3 ionized to give
carbonate anions. Na2CO3 2Na⁺ + CO3
2ˉ
Hydrolysis of carbonate anion gives strong alkaline NaOH, which is greatly ionized. While
carbonic acid produced, is a weak acid and is not greatly ionized. Thus, solution of Na2CO3
shows alkaline nature.
CO3
2ˉ
+ 2H2O H2CO3 + 2OHˉ
Overall reaction is
Na2CO3 +2H2O 2NaOH + H2CO3
Strong alkali weaker acid
14. Mention two major problems that may arise in Diaphragm cell? (lhr 2012, D.G
Khan 2008, 09,
Two problems we face in diaphragm cell. These are;
i) Cl-
produced can react with OH-
ions to give OCl-
ion.

9. Malik Xufyan
Cell # 0313-7355727
Cl2(g) + 2OH-
(aq) OCl-
(aq) + Cl-
(aq) + H2O
ii) OH-
may be attracted to anode where it can discharge to give O2 gas which makes the
liberated Cl2 impure.
15. What is plaster of paris? (lhr 2013,
When gypsum is heated at 100˚C it loses 3/4th
of its water and changes to plaster of Paris.
2CaSO4.2H2O CaSO4)2.H2O + 3H2O
Or
CaSO4 .H2O CaSO4.⅟2H2O + H2O
16. Why lime is added to acidic soil? (lhr 2014, D.G Khan 2013, 13,
Lime is added to the acidic soil. It controls the pH of soil and increase the readily soluble
phosphorous.
17. What is the action of litmus with aqueous solution of Na2CO3? (lhr 2014,
18. Alkali metals give ionic hydrides. Comment. (lhr 2015, D.G Khan 2008,
Ionic hydrides are formed by the complete giving of electron. Alkali metals are
electropositive and they give an electron. Therefore, Alkali metals react with hydrogen to
form ionic hydrides. For example:
2M + H2 2MH
At high temperature,
2Li + H2 2LiH
2Na + H2 2NaH
19. Prove decomposition of lithium nitrate, Give different products than nitrates of
other alkali metals. (lhr 2015,
Only lithium reacts with nitrogen to form nitrides. Other alkali metals not react with nitrogen.
For example,
6Li + N2 2Li3N(Lithium nitride)
20. Write formulas of a)Beryl b)asbestos (lhr 2015,
Beryl is Be3Al2(SiO3)6.
Asbestos is CaMg3(SiO3)4.
21. How lime and sand are used to make glass? (lhr 2015,
Lime and sand react at high temperature to form calcium silicate (CaSiO3). Calcium silicate
is further used in the formation of glass.
22. Why group IA elements are called alkali metals and IIA called alkaline earth
metals. (D.G Khan 2008,

10. Malik Xufyan
Cell # 0313-7355727
Because alkali metals are found in ashes of plants mainly consists of Na and K. Therefore, IA
group elements are called alkali metals. Alkaline earth metals form alkalies in water and are
widely distributed in nature. Therefore, they named as alkaline earth metals.
23. Point out role of lime in agriculture. (D.G Khan 2009,
The roles of lime in agriculture are:
i) CaO is used for neutralizing acidic soils.
ii) Application of lime to acidic soil increases the amount of readily soluble
phosphorous.
iii) CaO is used for making lime sulpher sprays which have a strong fungicidal action.
24. Give names and chemical formulas of two ores of calcium. (D.G Khan 2012,
25. What happens when
(i) Lithium carbonate is heated
Li2CO3 LiO + CO2
(ii) Lithium hydroxide is heated to red hot. (D.G Khan 2013,
2LiOH Li2O + H2O
red hot
Chap no 3
1. Why CO2 is acidic in character? (fsd 2008, D.G Khan 2011,)
CO2 dissolves in water to form a weak acid called carbonic acid. Further it neutralizes bases
to form salts. Hence, it has acidic nature.
2NaOH + CO2 Na2CO3 + H2O
CO2 + H2O H2CO3
2. Why Aluminum is not found free in nature? (fsd 2008,11,)
Aluminium is the third most abundant element that is found in earth crust. It is a very
reactive element; therefore, it does not freely occur in nature. But it generally exists in the
form of minerals of its oxides. E.g., Bauxite: Al2O3. 2H2O
3. What are silicates? Give one example. (fsd 2008)
Derivatives of silicic acid are called silicates.
It is prepared by fusing sodium carbonate with pure sand. It is done in a furnace called
reverberatory furnace.
Na2CO3 + SiO2 Na2SiO3 + CO2
4. How borax is converted into boric acid and vice versa? (fsd 2011, D.G Khan 2008,
Na2B4O7 + H2SO4 + 5H2O Na2SO4 + 4H3BO3
5. How will you convert boric acid into borax and vice versa? (lhr 2013,
4H3BO3 + 2NaOH Na2B4O7 + 7H2O
4H3BO3 + Na2CO3 Na2B4O7 + 6H2O + CO2
6. Give formula and use of soap stone. (fsd 2011,

11. Malik Xufyan
Cell # 0313-7355727
It is magnesium silicate, Mg3H2(SiO3)4. It is greasy to touch. It is used in making cosmetics
and household articles.
7. Aluminium is not found free in nature comment the statement. (fsd 2011,
Aluminium is the third most abundant element that is found in earth crust. It is a very
reactive element; therefore, it does not freely occur in nature. But it generally exists in the
form of minerals of its oxides. E.g., Bauxite: Al2O3. 2H2O
8. Discuss the chemistry of borax bead test and also define what is it? (fsd 2011, lhr
2013, D.G Khan 2012,
When borax is heated on loop, it is decomposed to give sodium metaborate and boric
anhydride and a glassy bead is produced.
Na2B4O7 2NaBO2 + B2O3
When given salt is heated on this bead, metallic oxides are produced which react with B2O3
to give colored metaborates of metals. Thus, metal cations can be identified.
9. Write names and formulas of different acids of boron. (fsd 2012, lhr 2014,
There are four important boric acids.
These are:
 Orthoboric acid (H3BO3).
 Metaboric acid (HBO).
 Tetraboric acid (H2B4O7).
 Pyroboric acid (H6B4O9).
10. Give the reactions of aluminum with dilute and concentrated H2SO4. (fsd 2012,
When aluminium reacts with dil. Acid, it gives hydrogen gas. Such as;
2Al + 6HCl 2AlCl3 + 3H2
When acids react with conc. sulphuric acid it gives SO2 gas.
2Al + 6H2SO4 Al2(SO4)3 + 3SO2 + 6H2O
11. What are chemical garden? (fsd 2012, 15, lhr 2014, D.G Khan 2013,
When crystals of soluble colored salts like nickel chloride, ferrous sulphate, cupper sulphate
or cobalt nitrate etc, are placed in a solution of sodium silicate, they produce a very beautiful
growth like plant. It is called chemical garden.
12. Write four uses of sodium silicate. (fsd 2013, 14, lhr 2014,
 It is used as filter for soap in soap industry.
 It is used in textile as a fire proof.
 It is used as furniture polishing.
 It is used in calico printing.
13. Why CO2 is gas and SiO2 is solid at room temperature? (fsd 2013, lhr 2012, 13, 14,
D.G Khan 2008,
CO2 exists as separate molecules, which have weak forces; therefore it is a gas at room
temperature.
SiO2 exist as polymer with altering Si and O atoms joined together to form big structure of
SiO2. Therefore, it is a solid.

12. Malik Xufyan
Cell # 0313-7355727
14. Liquid silicones are preferred over ordinary organic lubricants. Why? (fsd 2014,
lhr 2008, D.G Khan 2012,
Some methyl silicones are oily liquid. The viscosity of silicones incases with increases in
chain length. These are used in ordinary organic lubricants. Because these liquids are mixed
with greases or used as oil in bearings, gear etc.
15. What is the action of litmus with aqueous solution of borax? (fsd 2015,
16. How the glassy mass is produced from borax? (lhr 2008,
When borax is heated on loop, it is decomposed to give sodium metaborate and boric
anhydride and a glassy bead is produced.
Na2B4O7 2NaBO2 + B2O3
17. What is the effect of heat on Orthoboric acid? (lhr 2009, 14,
18. What are silicones? (lhr 2009, D.G Khan 2012,
The polymers having backbone of altering Si oxygen atoms with non-polar side chain are
called silicones.
19. Why CO2molecule is non-polar in nature? (lhr 2009, D.G Khan 2009,
CO2 is a triatomic molecule. It has a double bond between carbon and oxygen. CO2 molecule
is formed by covalent bond. Covalent bonded molecules are not soluble in water. Therefore,
CO2 molecule is non-polar in nature.
20. How weathering phenomena convert potassium fled spar into clay? (lhr 2010,
China wares are made from a mixture of kaolin bone ash and feldspar. The mixture is fused
on heating and fills the pores between the grains of kaolin. Kaolin is a pure clay and it is
white in color.
21. How nitrogen dioxide is prepared from a) lead nitrate b)Cu+HNO3? (lhr 2010,
D.G Khan 2009,
Lead nitrate:
2Pb(NO3)2 2PbO + 4NO2 + O2
From Cu + HNO3:
Cu + 4HNO3 Cu(NO3)2 + 2H2O + 2NO2
22. How Al finds its uses in metallurgy and photoflash bulbs? (lhr 2011,
23. Show that H3BO3 is mono boric acid? (lhr 2011, D.G Khan 2013,

13. Malik Xufyan
Cell # 0313-7355727
24. Give uses of lead sub oxide? (lhr 2011,
25. Define metalloid. Give reaction of a metalloid of group 3-A with oxygen. (lhr 2011,
26. Borate glazes are better than silicate glazes .explain. (lhr 2012,
27. Write two principal uses of borax. (lhr 2012,
28. Write down the formulas of borax and corundum. (lhr 2013,
29. Write the reaction of boric acid and Orthoboric acid with 1)ethyl alcohol
2)NaOH (lhr 2014, 15, D.G Khan 2011,
30. Explain structure of CO2? (lhr 2015,
31. How aqueous solution of borax is alkaline? (lhr 2015,
32. Give two similarities between carbon and silicon. (lhr 2015,
33. Give the names and formulas fox four oxy acids of boron. (D.G Khan 2008,
34. Give the formula of white lead Also give its one use. (D.G Khan 2009,
35. Justify that the aqueous solution of borax turns red litmus blue. (D.G Khan 2009,
36. What is asbestos? Give its uses. (D.G Khan 2009,
37. What are semiconductors? Give their two applications. (D.G Khan 2009,
38. Point out four such properties in which white Phosphorous is different from red
Phosphorous. (D.G Khan 2009,
39. Justify carbon and hydrogen is reducing agents. (D.G Khan 2011,
40. Outline any four uses of aluminum. (D.G Khan 2011, 13,
41. Give the formula of tincal and mica. (D.G Khan 2011,
42. Write the names of any two lead pigments with their color. (D.G Khan 2012,
43. What is peculiar behavior of Boron? Give four points. (D.G Khan 2012,
44. What is quartz? How is it different from CO2? (D.G Khan 2012,
45.
Chap no 4
1. Define dehydrating agent and write a chemical equation in which H2SO4 acts as
Nitric acid? (fsd 2008)
2. What is meant fuming nitric acid? (fsd 2008)
It the solution contains more than 86% nitric acid, then; this solution is called fuming nitric
acid. pure nitric acid gives us white fumes in air and this form of nitric acid is called white
fuming nitric acid. While nitric acid when dissolved in NO2 gives reddish brown fumes, it is
called red fuming nitric acid.
3. Write two reaction of nitrogen dioxide with: (i) KI (ii) K2S (fsd 2010,
(i) KI
H2S + NO2 H2O + S + NO
(ii) H2S
2KI + 2NO2 2KNO2 + I2