This document contains a chemistry exam with multiple choice and subjective questions covering various topics in chemistry including stoichiometry, atomic structure, chemical bonding, solutions, equilibrium, and thermochemistry. The exam has two sections - the first with 22 short answer questions and the second containing 3 long answer questions to attempt. Some sample questions ask about the mass of an electron, diffusion vs effusion of gases, ionic character of hydrogen halides, quantum numbers and their significance, classification of atomic orbital hybridization, and balancing chemical equations using oxidation numbers.

1. Malik Xufyan 0313-7355727
FAISALABAD BOARD 2007
Paper: Chemistry (Part 1) (Objective Type)
Time: 20 Minutes Marks: 17
Note: Four answers are given against each column A, B, C and D. Select the right answer and on the separate answer sheet, fill the circle A, B, C and
D with pen or marker in front of question number.
A B C D
1
The mass of 1 mole of electron is: 1.008g 0.55mg 0.184mg 1.673mg
2
An ordinary microscope can measure size of object up
to:
100 nm 200 nm 400 nm 500 nm
3
Solvent extraction in equilibrium process and it is
controlled by:
Law of mass
action
The amount of
solvent used
Distributive law
The amount of
solute
4
The order of rate of diffusion of gases 𝑁𝐻 , 𝑆𝑂 , 𝐶𝑙
and 𝐶𝑂 is:
𝑁𝐻 > 𝑆𝑂 > 𝐶𝑙
> 𝐶𝑂
𝑁𝐻 > 𝐶𝑂 > 𝑆𝑂
> 𝐶𝑙
𝐶𝑙 > 𝑆𝑂 > 𝐶𝑂
> 𝑁𝐻
𝑁𝐻 > 𝐶𝑂 > 𝐶𝑙
> 𝑆𝑂
5 In orthorhombic crystal the unit cell dimensions are:
𝑎 = 𝑏 ≠ 𝑐
𝛼 = 𝛽 = 𝛾 = 90
𝑎 ≠ 𝑏 ≠ 𝑐
𝛼 = 𝛽 = 𝛾 = 90
𝑎 ≠ 𝑏 ≠ 𝑐
𝛼 = 𝛽 ≠ 𝛾 = 90
𝑎 ≠ 𝑏 ≠ 𝑐
𝛼 = 𝛽 = 𝛾 ≠ 90
6 The volume of ice increases then liquid water by: 5% 9% 12% 15%
7
Splitting of spectral lines when atoms are subjected to
strong electric field is called:
Zeeman’s effect Stark effect
Photo electric
effect
Compton effect
8 Balmer series is found in: L.R region U.V region Visible region None
9
Which of hydrogen halides has highest percentage of
ionic character?
HCl HBr HF HI
10 The geometry of 𝐵𝑒𝐶𝑙 is: Linear Plane triangular Tetrahedral None
11 1 calories is equivalent to: 0.4184 J 41.84 J 4.184 J 418. 4J
12 In case when [𝑂𝐻 ] > [𝐻 ] the solution is: Acidic Neutral Basic None
13
The azeutropic mixture of solution showing positive
deviation can be distillated at _________ boiling point:
Maximum Minimum No sharp None
14 The hydrogen energy of Br ion is ______ the F ion: Equal to Smaller than Greater than None
15 The oxidation number of 𝑀𝑛 in 𝐾𝑀𝑛𝑂 : 3 5 7 9
16
If salt bridge is not used between two half cells then
the voltage:
Decreases rapidly Decreases slowly Does not change Drops to zero
17
With increase of 10℃ temperature, the rate of reaction
becomes double. This increase in rate of reaction is due
to:
Decrease in the
activation energy
of reaction
Decrease in
number of
collision between
the molecules
Increase in
activation energy
reactants
Increase in number
of effective
collision

2. Malik Xufyan 0313-7355727
SECTION-I
2. Attempt any 22 short questions: ( 44)
(i) Justify the statement: 23 gram of sodium and 238 gram of
uranium have equal number of atoms.
(ii) What is stichiometry and define yield of chemical reaction?
(iii) How limiting reactant controls the amount of mass has to be
obeyed during stoichiometric calculations.
(iv) Give reasons that law of conservation of mass has to be
obeyed during stoichiometric calculations.
(v) Why is there a need to crystallize the crude products?
(vi) Which solvent are mostly used in crystallization?
(vii) Justify that 1𝑐𝑚 of 𝐻 and 1𝑐𝑚 of 𝐶𝐻 at STP will have
same number of molecules whereas one molecule of 𝐶𝐻 is
8 times heavier than that of Hydrogen?
(viii) Differentiate between diffusion and effusion of gases?
(ix) Why do we fell uncomfortable breathing at higher altitudes?
(x) Evaporation takes place at all temperatures. Explain with
reason.
(xi) Why boiling point of water is is different at Murree hills and
at Mount Everest?
(xii) Explain with reasons that ionic crystals are highly brittle?
(xiii) Define Isomorphism and polymorphism in the crystalline
solids and give examples?
(xiv) Why it is necessary to decrease the pressure in the discharge
tube to get the cathode rays?
(xv) Why e/m value of the cathode rays is just equal to that of
electron?
(xvi) Justify that the distance gaps between different orbits go on
increasing from the lower to the higher orbits?
(xvii) Give the Moseley’s equation. Also write its importance?
(xviii) Why ionization energy decreases within a group and
increase along a period?
(xix) No bond in chemistry is 100% ionic. Justify it.
(xx) Define bond energy and bond length?
(xxi) Pi bonds are more diffused than sigma bonds. Explain with
reasons?
(xxii) Explain the enthalpy of formation (∆𝐻 ) and entholpy of
atomization (∆𝐻 ).
(xxiii) Differentiate between exothermic and endothermic
reactions?
(xxiv) The change of volume disturbs the equilibrium position for
some of the gaseous phase reactions, but not the equilibrium
constant. Why?
(xxv) Why do we need buffer solution in daily life?
(xxvi) The concentration in terms of molality is independent of
temperature but molarity depends upon temperature. Give
reasons.
(xxvii) How do you justify that boiling point of the solvents
increase due to presence of solutes?
(xxviii) Explain the difference between electrolyte cell and voltaic
cell?
(xxix) Give reason that a porous plate or salt bridge is not required
in the lead storage cell?
(xxx) Calculate the oxidation number of chromium in:
(1) 𝐶𝑟 𝑂 (2) 𝐾 𝐶𝑟 𝑂
(xxxi) Differentiate between rate and rate constant of a reaction?
(xxxii) Define: (i) Catalytic poisoning (ii) Enzyme catalyst
(xxxiii) One mole solution of urea is dilute in water as compared to
one molar solution of urea, but the number of particles of
solute is same, Justify it?
SECTION-II
Note: Attempt any THREE questions
3. (a) Describe manometric method for the measurement of vapour
pressure?
(b) An organic compound having molecular mass 116, on
combustion analysis gives 40.92% carbon and 4.58% hydrogen. Find
out the molecular formula of such compound?
4. (a) What are quantum numbers? Discuss their significance?
(b) Calculate the number of molecules in the given amount of
each gas:
(1) 20.0 𝑐𝑚 of 𝐶𝐻 at 0 𝐶 and pressure 700 mm of 𝐻𝑔
(2) 1.0 𝑐𝑚 of 𝑁𝐻 at 100 𝐶 and pressure of 1.5 𝑎𝑡𝑚
5. (a) Define and classify atomic orbital hybridization. Discuss the
structure of 𝐵𝐹 in the light of orbital hybridization.
(b) Explain briefly energy of activation?
6. (a) Define the following: (1) Surrounding (2) Standard enthalpy
of atomization (3) Standard enthalpy of solution
(b) What are non – ideal solutions? Discuss their types with
example.
Time: 02:40 Hours (Subjective Type) Marks: 68

3. Malik Xufyan 0313-7355727
7. (a) Balance the following equations by oxidation number method:
(1) 𝐵𝑟 + 𝑁𝑎𝑂𝐻 ⎯⎯⎯⎯⎯⎯ 𝑁𝑎𝐵𝑟𝑂 + 𝐻 𝑂
(2) 𝑁𝑎𝐶𝑙 + 𝐻 𝑆𝑂 + 𝑀𝑛𝑂 ⎯⎯⎯⎯ 𝑁𝑎 𝑆𝑂 + 𝑀𝑛𝑆𝑂 + 𝐻 𝑂 + 𝐶𝑙
(b) 𝑁 and 𝐻 combine to give 𝑁𝐻 ( ). The value of 𝐾 in this
reaction at 500 𝐶 is 6.0 × 10 . Calculate the value of 𝐾 for this
reaction.