RAWALPINDI BOARD 2016
PAPER CHEMISTRY
PART-I
Time: 20 Min. (Objective Part) Marks: 17 Note: You have four choice for each objective type question as A, B, C and D. The choice which you think is correct; fill that circle in front of that question number. Use marker or pen to fill the circles. Cutting or filling two or more circles will result in zero mark in that question.

Question#1

• The volume occupied by 1.4g of N₂ at STP is:
  
  (a) 2.24 dm³
  (b) 22.4 dm³
  (c) 1.12 dm³
  (d) 112 cm³
  
  
• 27g of Al will react completely with how much mass of O² to produce Al₂O ₃.
  
  (a) 8 g of oxygen
  (b) 16 g of oxygen
  (c) 32 g of oxygen
  (d) 24 g of oxygen
  
  
• The comparative rates at which the solute move in paper chromatography depends on:
  
  (a) The size of paper
  (b) R_f values of solutes
  (c) Temperature of the experiment
  (d) Size of the chromatographic tank
  
  
• The number of molecules in one dm3 of water is close to:
  
  (a) 6.02/22.4x10²³
  (b) 12.04/22.4x10²³
  (c) 18/22.4 x10²³ 
  (d) 55.6 x 6.02 x10²³
  
  
• A real gas obeying Vanderwaal's equation will resemble ideal gas if:
  
  (a) Both 'a' and 'b' are large
  (b) Both 'a' and 'b' are small
  (c) 'a' is small 'b' is large
  (d) 'a' is large 'b' is small
  
  
• Acetone and chloroform are soluble into each other due to:
  
  (a) Intermolecular hydrogen bonding
  (b) Ion-dipole interaction
  (c) Instantaneous dipole
  (d) Debye forces
  
  
• The molecules of CO2 in dry ice form the:
  
  (a) Ionic crystals
  (b) Covalent crystals
  (c) Molecular crystals
  (d) Any type of crystal
  
  
• Splitting of spectral lines when atoms are subjected to strong electric field is called:
  
  (a) Zeeman effect
  (b) Stark effect
  (c) Photoelectric effect
  (d) Compton effect
  
  
• Quantum number values for 2P orbitals are:
  
  (a) n=2,l=1
  (b) n=1, l=2
  (c) n =1, l =0
  (d) n=2,l=0
  
  
• Which of the following species has unpaired electrons in antibonding molecular orbitals?
  
  (a) O²⁺₂
  (b) N₂^2-
  (c) B₂
  (d)F₂
  
  
• Which of the following hydrogen halides has the highest percentage of ionic character
  
  (a) HCI
  (b) HBr
  (c) HF
  (d) HI
  
  
• Calorie is equivalent to:
  
  (a) 0.4184 J
  (b) 41.84 J
  (c) 4.184 J
  (d) 418.4 J
  
  
• The solubility product of AgCI is 2.0 x10^-10 mole² dm^-6 . The maximum concentration of Ag⁺ ions in the solution is:
  
  (a) 2.0 x 10^-10 mole dm^-3
  (b) 1.41 x 10^-5 mole dm^-3
  (c) 1.0 x 10^-10 mole dm^-3
  (d) 4.0 x 10^-24 mole dm^-3
  
  
• The pH of 10^-3 mol dm^-3 of an aqeous solution of H₂SO₄ is.
  
  (a) 3.0
  (b) 2.7
  (c) 2.0
  (d) 1.5
• Molarity of pure water is:
  
  (a) 1
  (b) 18
  (c) 55.5
  (d) 6
• The oxidation number of 'O' atom in OF₂ is:
  
  (a) +2
  (b) -2
  (c) +1
  (d) -1
  
  
• In Zero order reaction, the rate is independent of:
  
  (a) Temperature of reaction
  (b) Concentration of reactants
  (c) Concentration of products
  (d) Pressure of reactants

Time: 2:40 Hours
(Subjective Part)
Marks: 68
Section I

2.Attempt any EIGHT short questions. (8x2=16)

• Define stoichiometry and give two assumptions for stoichiometeric calculations.
• Differentiate between adsorption and partition chromatography.
• (What is meant by the term critical solution temperature? Also give value of critical solution itemperatire and composition of phenol water system at critical temperature.
• State Lechatlier's principle. What is the effect of change in pressure on the following reaction? N₂ + 3H₂ 2NH _{3 _}_____2 NH_{3_______}
• Calculate mass in Kg of 2.6 X 10 ²⁰ molecules of SO₂.
• Why actual yield is usually less than the theoretical yield?
• How crystals are decolourised?
• Convert -40°C into Fahrenheit.
• Define mole fraction and give its mathematical form.
• Why deep sea divers take oxygen mixed with an inert gas?
• Define hydrates and give its two examples.
• Derive formula to determine density from an ideal gas equation.

3.Attempt any EIGHT short questions. (8 x 2 = 16)

• Define hydrogen bonding. Show hydrogen bonding in ammonia molecule.
• In summer the antifreeze solutions protect the radiators from boiling over. How?
• Write down the reaction at anode and cathode of silver oxide battery in a basic electrolyte.
• Define crystalline solids and crytallites.
• Define transition temperature. Give two examples.
• Define crystallographic elements.
• Narrate four properties of cathode rays.
• Define slow neutrons and fast neutrons.
• State Mosely's law and write down its equation.
• Write the electronic configuration of Si = 14 and Cr = 24.
• Define electrolytic cell.
• Define standard electrode potential.

4.Attempt any SIX short questions. (6 x 2 = 12)

• Define ionization potential. Give two factors on which it depends.
• CO, molecules have linear structure while H2O have angular structure. Explain.
• Under what conditions activated complex is formed?
• Define Octet rule.
• If - bonds are diffused than sigma bonds. Explain.
• Define state function with an example.
• State with one example enthalpy of combustion.
• Define order of reaction with an example.
• What is auto-catalysis? Give an example.

SECTION-11:

Attempt any THREE questions. (8x 3=24)
Question#5
(a) The combustion analysis of an organic compound shows it to contain 65.44% carbon, 5.50% hydrogen and 29.06% of oxygen. What is the emperical formula of the compound? If the molecular mass of this compound is 110.15gmori Calculate the molecular formula of the compound.
(b) What are liquid crystals? Give their three uses in daily life.

Question#6
(a) State Graham's law of diffusion and demonstrate this law with diagram.
(b) Write the main postulates of Bohr's theory.

Question#7
(a) Describe sp2 hybridization giving example of Ethene.
(b) Write a note on Hess's law of constant heat summation with one example.

Question#8
(a) Describe the method to determine the rate of reaction by a chemical method.
(b) The solubility of CaF, in water at 25°C is found to be 2.05x10^-4 mol din^-3 . What is the value of Ks, at this temperature. Atomic mass of Ca = 40, F = 19.

Question#9
(a) What are azeotopic mixtures. Discuss positive deviation from Raoult's law.
(b) Write a note on Nickel Cadmium cell.