Multan Board 2017
Chemistry
PART - I
Time: 30 Minutes
Group 1
Note: Write answers to the questions on the objective answer sheet provided. Four possible answers A, B, C and D to each question are given. Which answer you consider correct, fill the corresponding circle  A, B, C and D given in front of each question with Marker or pen ink on the answer sheet provided.

• _____was derived by C.M. Goldberg and P. Wage in 1864.

1. Law of Conservation of Mass
2. Law of Mass Action
3. Distribution Law
4. Lass of Conservation of Energy

• 18 g glucose is dissolved in 90 g of water. The relative lowering of vapour pressure is equal to:

1. i
2. 5.1
3. 6
4. 7

• The potential of standard Hydrogen Electrode is arbitrarily taken as:-

1. 1.00
2. 0.00
3. 5.00
4. 3.00

• Glucose is converted into ethanol by the enzyme:-

1. Invertase
2. Urease
3. Zymase
4. Surase

• The volume occupied by 1.4g of AL at S.T.P is:-

1. 2.24 dm³
2. 22 A dm³
3. 1.12dm³
4. 112cm³

• The number of Isotopes of Cadmium is:-

1. Six
2. Seven
3. Five
4. Nine

• Chromatography in which the stationary phase is a solid is classified as:-

1. Partition Chromatography
2. Gas Chromatography
3. Adsorption chromatography
4. Thin layer Chromatography

• The molar volume of CO₂ is maximum at:-

1. S.T.P
2. 127°C and 1 atm
3. 0°C and 2atm
4. 273°C and 2atm

• Pressure remaining constant at which temperature the volume of a gas will become twice of what it is at 0°C.

1. 546°C
2. 200°C
3. 546 K
4. 273 K

• When water freezes at 0° C, its density decreases due to:-

1. Empty spaces present in the structure of ice
2. Cubic structure of ice
3. Change of bond lengths
4. Chang of bond angles

•  is a pseudo solid.

1. CaF₂
2. Glass
3. Nad
4. KCI

• When 6d orbital is complete, the entering electron goes into:-

1. 7f
2. 7s
3. 7p
4. 7d

• The wave number of the light emitted by a certain source is 2 x 10⁶m^-1 The wavelength of this light will be:-

1. 500nm
2. 500m
3. 200nm
4. 5 x 10⁷

• The H-H bond energy in KJmoles^-1 is:-

1. 346
2. 436
3. 463
4. 336

• ____has zero dipole moment.

1. NH₃
2. CHCl₃
3. H₂O
4. BF₃

• The change in heat energy of a chemical reaction at constant temperature and pressure is called:-

1. Enthalpy change
2. Heat of sublimation
3. Bond energy
4. Internal energy change

• The pH of 10^-3 mole dm^-3 of an aqueous solution of H₂SO₄ is:-

1. 3.0
2. 2.7
3. 2.0
4. 1.5

SUBJECTIVE PART
SECTION B

2. Write short answers to any EIGHT (8) questions.

1. What is Stoichioinetry? Give its two assumptions.
2. What are Molecular Ions? How are they generated?
3. Define grain Formula. Give two examples.
4. What is the basic principle of Crystallization?
5. State Distribution Law.
6. What is R value? Give its formula.
7. What is the difference between Diffusion and Effusion?
8. Define Critical Temperature and Critical Pressure of Gases.
9. Calculate the value of car constant "R" in S.I units.
10. Define Solubility Product. Give one example.
11. How does a catalyst affect a Reversible Reaction?
12. What is the effect of increase of Pressure on the decomposition of PCl₅?

3. Write short answers to any EIGHT (8) questions.

1. Why HF is the weakest acid than other Hydrogen Halides.
2. Evaporation takes place at all temperature Justify.
3. Define Isomorphism and Polymorphism.
4. Why ionic crystal do not conduct electricity in the solid state?
5. Differentiate between Zeeman Effect and stark effect.
6. Whichever gas is used in the discharge tube, the nature of the cathodes rays remains the same. Why?  
7. Give two postulates of Bohr's atomic model.
8. Why positive rays are also called canal rays?
9. Define Molarity and Molality.
10. What is meant by Water of Crystallization? Dive two examples.
11. Differentiate between electrolytic and Voltaic Cell.
12. A salt bridge maintains the electrical neutrality in the cell. Justify.

4. Write short answers to any SIX (6) questions.

1. Why the Ionization Energy decreases down the group. Although nuclear charge increases?
2. How nature of bond can be determined by Electronegativity’s Values?
3. How can you describe that π bends are more diffused than σ-bonds?
4. The dipole moments of CO₂ and CS₂ are zero but that of SO₂ is 1.61 D. why?
5. What is State and State function? Explain with example.
6. Prove that ΔE = q_v
7. How surface area affects the rate of reaction?
8. Differentiate between Homogeneous and Heterogeneous Catalysis.
9. Differentiate between Instantaneous and Average Rate of Reaction.

SECTION C

Note: Attempt any THREE questions.
Q 5.

1. A well-known ideal gas is enclosed in a container having volume 500cm3 at S.T.P Its mass comes out to be 0.72 gram. What is the motor mass of this gas?
2. Define Vapour Pressure. How vapour pressure is measured by Manometric Method?

Q 6.

1. Write eight postulates of Kinetic Molecular Theory of Gases.
2. How charge to mass (e/m) ratio of electron is measured?

Q 7.

1. Give four postulates of Valence Shell Electron Pair Repulsion Theory.
2. Describe Bomb Calorimeter.

Q 8.

1. The solubility of PbF₂ at 25ois 0.64 gmdm-3.Calculate Ksp of PbF₂.
2. Explain construction and working of standard Hydrogen Electrode (SHE).

Q 9.

1. Define Colligative Properties. Hors molecular mass of solute is determined by lowering in vapour pressure?
2. What is meant by Enzyme Catalysis? Write reaction showing the catalysis of urea.