Inter (Part-I) Fedral Board 2014
Chemistry 
Part I (Objective Type)
Time Allowed: 20 Minutes 
Max. Marks: 17

Note: Four possible answers A, B, C and D to each question are given. The choice which you think is correct, fill that circle in front of that question with Marker or Pen ink in the answer-book. Cutting or filling two or more circles will result in zero mark in that question.

Question#1. Circle the correct option i.e. A/B/C/D. Each part carries one mark.

• Mass of 6 .02 x 10²³ electrons is

A) 1.008 mg
B) 0.55 mg
C) 0.184 mg
D) 1.673 mg

• The largest number of molecules is present in

A) 3.6g of H₂O
B) 4.8g of C₂H₅OH
C) 2 .8g of CO
D) 5.4g of N₂O₅

• The comparative rates at which the solutes move in paper chromatography depends on:

A) Size of paper
B) R_f values
C) Temperature of the experiment
D) Size of chromatographic tank

• Acetone and chloroform are soluble in each other due to:

A) Intermolecular Hydrogen Bonding
B) Ion-dipole interactions
C) Instantaneous dipoles
D) All of these

• Ionic solids are characterized by

A) Low melting points
B) Good conductivity in solid state
C) High vapour pressure
D) Solubility in polar solvents

• Number of molecules in one dm³ of water is close to:

A) 6.02/22.4 x 10²³
B) 12.04/22.4 x 10²³
C) 18/22.4 x 10²³
D) 05.6 x 6.02 x 10²³

• Quantum number values for 3d orbitals are

A) n 3, 1= 2
B) n =3, 1= 3
C) n=2 , 1=3
D) n =2 , 1 = 3

• Bohr Model of Atom is contradicted by:

A) Planck's Quantum theory
B) Dual nature of matter
C) Heisenberg's un-certainty principle
D) All of these

• Enthalpy of Neutralization of all the strong Acids and strong Bases has the same value because: 

A) Neutralization leads to the formation of salt and water
B) Strong Acids and Bases are ionic substances
C) Acids always give rise to H⁺ and Bases give rise to OH-ions
D) The net chemical change involve the combination of H⁺ and OH- to form Water

• Which of the following Hydrogen Halides has the highest percentage of ionic character?

A) HCI
B) HBr
C) HF
D) HI

• The pH of 10-3 moles dm-3 of an aqueous solution of H₂SO₄ is ______________.

A) 3.0
B) 2.7
C) 2.0
D) 1.5

• Which of the following solutions has the highest boiling-point?

A) 5.85% NaCI solution
B) 18.0% glucose solution
C) 6.0% urea solution
D) All have the same Boiling-points

• The product obtained at Anode by the electrolysis of an aqueous solution of H₂SO₄ using an inert electrode  is

A) O₂
B) H₂
C) SO₂
D) S

• If salt bridge is NOT used between two half cells then the voltage of a cell.

A) Decreases rapidly
B) Decreases slowly
C) Does not change
D) Drops to zero

• Which order of reaction obeys the expression t5/2 = 1/Ka?

A) First order
B) Second order
C) Third order
D) Zero order

• According to Molecular orbital theory, electrons in the molecular orbitals are filled according to_______.

A) Aufbau's Principle
B) Pauli's exclusion principle
D) Hund's rule
C) All of these

• The equation for determination of heat of neutralization by using Glass Calorimeter is:

A) q=m x S x ∆ T
B) E=m x S x ∆ T
C) q=m x c x ∆ T
D) ∆E =qv

CHEMISTRY HSSC-I
SECTION B

2 Attempt any FOURTEEN parts. The answer to each part should not exceed 5 to 6 lines.

• A compound contains the Elements of C, H and CI in the molar ratios C : H : CI, 3 : 2 :1 What is the empirical formula of this compound? Also find the molecular formula of this compound if its molecular mass is 147 g / mol. 03
• What is a limiting reactant? How does it control the quantity of the product formed, Give one example.
• Define chromatography. How distribution coefficient (k) helps in the distribution of the components of a mixture in chromatography?
• 250cm³ of the sample of Hydrogen effuses four times as rapidly as 250 cm³of an  unknown gas. Calculate the molar mass of unknown gas.
• What type of intermodular forces is present in the following?
  • Ammonia NH₃
  • Octane (C₈H₁₈)
  • Argon (Ar)
  • Propanone
  • Methanol
  • HF
• Why is diamond an Electrical insulator while Graphite is a good conductor of Electricity?
• Define the following with examples.
  • Isomorphism
  • Transition Temperature
• Calculate the energy, frequency and wave length of radiations emitted when an electron drops from n = 4 to n = 2 of Hydrogen Atom.
• Discuss Chadwick's experiment for the discovery of Neutron in an Atom.
• Define Ionization energy by giving an example. Also name the factors affecting it.
• Differentiate between Sigma (ϭ) and Pi (π) Bond. Why π - bonds are more diffused  than a bond?
• Explain the molecular orbital structure of N₂ molecule. 
• Draw a fully labelled Born-Haber cycle for the formation of potassium Bromide (K Br).
• What is Lowry Bronsted idea of Acids and Bases? Explain conjugate Acids and Base.
• Why do the rates of forward reactions slow down when a reversible reaction  approaches the equilibrium stage?
• What is critical solution temperature? Explain by giving the example of Phenol - water system.
• Define Galvanic cell. Draw a labelled diagram of a cell consisting of Zu - Cu  Electrodes.
• The sum of the exponents in the rate equation may or may not be the same as in a balanced chemical equation. Justify this statement by giving any two examples.
• What is Energy of activation? How Can energy of activation be calculated from Arrhenius equation?

SECTION - C

Note: Attempt any TWO questions. All questions carry equal marks. (2 x13 = 26)

Question#3
a) Calculate the number of grams which can be prepared by reacting 20 g of Al with 30 g of S. How much of the non-limiting reactant is in excess? The reaction between Al and S is given as: 2A1+ 3S, A1=S3 (At masses: S = 32, Al = 27)
b) Derive Boyle's Law and Grahm's law of diffusion of Gases on the basis of Kinetic molecular theory of Gases.
c) Write any three uses of plasma.

Question#4

a) Keeping in mind the postulates of Bohr's model of an Atom, derive an expression for energy of revolving electron in nth orbit of Hydrogen Atom.
b)What is (n + l) rule of distribution of electrons in sub-shells of an Atom? Give examples.
c) Explain the shape of Ethyne on the basis of Atomic orbital Hybridization.

Question#5
a) Give a graphical explanation of Elevation of Boiling-point of a solution. How molar mass of a non volatile and non Electrolyte solute can be determined with the help of it?
b) Differentiate between Zeotropic and Azeotropic mixtures with the help of examples.
c) Write Redox reactions taking place at Anode and cathode during discharging and recharging of Lead Accumulator (car battery).