Chemistry past paper 2014
Gujranwala Board
Part-I
Note:you have four choices 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 coircles will result in zero mark in that question. Attempt as many question as given in objective type question paper and leave others blank.

• The number of moles of CO₂which contain 8.0 g of oxygen is

(a)25
(b) 0.50
(c) 1.0
(d)1.50

• The volume occupied by 1.4g of N₂ at S.T.P is:

(a) 24dm³
(b) 22.4 dm³
(c) 1.12dm³
(d) 112dm³

• The comparative rates at which the solutes move in paper chromatography, depend upon

(a) the size of paper
(b) R_f values of solutes
(c) temperature of experiment
(d) size of the chromatographic tank used

• Solvent extraction is an equilibrium process and it is controlled by

(a) law of mass action
(b) amount of solvent
(c) amount of solute used
(d) distribution law

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

(a)546°C
(b) 200°C
(c) 546K
(d) 273K

• The molar volume of CO₂ is maximum at

(a) STP
(b) 127°C and 1 atm
(c) 0°C and 2 atm
(d) 273°C and 2 atm

• London dispersion forces are the only forces present among the

(a) Molecules of water in liquid state
(b)Atoms of helium in gaseous state at high temperature
(c)Molecules of solid iodine
(d) Molecules of hydrogen chloride gas

• Which is a pseudo solid?

(a) CaF₂
(b) glass
(c) NaCl
(d) all

• In the ground state of an atom, the electron is present

(a) in the nucleus
(b) in the second shell
(c) nearest to the nucleus
(d) farthest from the nucleus

• When 6d orbital is complete, the next electron goes into

(a) 7f
(b) 7s
(c) 7p
(d) 7d

• Which has the highest percentage of ionic character?

(a) HCl
(b) HBr
(c) HF
(d) HI

• Which has zero dipole moment?

(a) NH₃
(b) CHCl₃
(c) H₂O
(d) BF₃

• One calorie is equivalent to

(a) 0.4184J
(b) 41.84J
(c) 4.184J
(d) 418.4J

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

(a)0
(b)7
(c)0
(d)5

• Molarity of pure water is

(a) 1
(b)18
(c) 55.5
(d) 6

• Stronger the oxidizing agent, greater is the

(a) oxidation potential
(b) reduction potential
(c) redox potential
(d) EMF of the cell

• The unit of the rate constant is the same as that of the rate of reaction in

(a) first order reaction
(b) second order reaction
(c) zero order reaction
(d) third order reaction

(Section-I)

Question #2: Write short answers to any EIGHT (8) questions:

• Mg atom is twice heavier than that of carbon atom justify.
• N₂ and CO have the same number of electrons, protons and neutrons. Explain.
• Write two assumptions of stoichiometry.
• Give statement of ‘distribution Law’.
• Different between stationary and mobile phase used in chromatography.
• Water vapours do not behave ideally at 273K. justify
• Calculate the value of general gas constant ‘R’ in S.I. units.
• Write two applications of plasma.
• Why the boiling points of noble gases increases down the group?
• Gasoline evaporates much faster than water. Give reason.
• What are crystallographic elements?
• The electrical conductivity of metals decrease with the increase in temperature. Why?

Question #3 Write short answers to any EIGHT (8) questions:

• Why the nature of cathode rays is independent of the nature of the gas used in discharge tube?
• Write down nuclear reactions involved in the conversion of Cu into Zn
• Mention two defects of Bohr’s model.
• How the wave nature of electron was verified experimentally?
• Why the radius of an atom cannot be determined precisely?
• How the electronegativity difference of two bonded atom can be used to predict the ionic/covalent nature of the bond?
• NH₃ and NF₃ have different bond angles. Justify.
• Why π-bonds are more diffused than σ-bonds?
• Define a spontaneous reaction.
• The enthalpy of neutralization of all the strong acids and strong bases has the same value justify.
• How the value of kc of a reaction helps to predict the direction of a reversible reaction?
• What will be the effect of change of pressure on the synthesis of NH₃?
  N₂(g) +3H₂(g) 2NH_2(g)

Question #4 Write short answers to any SIX (6) question: (2×6=12)

• Define solubility prodect. Give its one application:
• Cane sugar cannot be dissolved in benzyne. Give reaspon.
• Many solution do not behave ideally. Give reason.
• Lowering of vapour pressure is colligative property. Explain.
• What are the function of the salt bridge?
• What is electtrode pontential?
• Impure copper can b unpurified by electrolytic proces. Explain.
• Differentiate between homogeneous catalysis and heterogeneous catalysis.
• Radioactive decay is first order reaction. Justify.

(SECTION-II)

• (a) What is mass spectrometer? How is it used to determine the relative atomic Massesof issotopes? (4)
  (b) What are the malecular solids? Write their properties. (4)

• (a) Give the postulates of VSEPR theory. (4)
  (b) State the construction and functioning of glass calorimeter. (4)

• (a) 250 cm³ of the sample of hydrogen effuses four times as rapidly as 250cm³ of an unknown gas. Caculate the molar mass of an unknown gas. (4)
  (b) Give the different postulates of Bohr,s Atomic Model. (4)

• (a) N_2(g) and H_2(g) combine to give NH_3(g). The value of k_c in this reaction at 500°c is 6.0×10^-2. Calculate the value of k_p for this reaction. (4)
  (b) Outline the important industrial application of electrolysis. Write the Electrochemical reaction involved therein. (4)

• (a) How desression is freezing point is measured by Beckmann`s apparatus? (4)
  (b) write four characteristics of a catalyst. (4)

(SECTION-III)
(Pactical)

(i) Write down standard solution, chemical equation with mole ratio, indicator with end poit, procedure and supposed reading with calculation for part A,B & C.
(1+1+1+1+1) = 5

(ii) Write down material required< diagram and procedure for part D & E. (1+113) = 5

10.(a) Determine percentage purity of Na₂co₃ in the given solution containing 10gm of impure Na₂co₃ sample per dm³. Mol. Mass Na₂s₂o₃ = 106 (5)

(b) 12gm of (NH₄)₂C₂O₄ and (NH₄)₂SO₄ have been dissloved per dm_3. Find out percentage composition volumetrically. Mol mass (NH₄)₂C₂O₄ =110 (5)

(c) 30 g of Na₂S₂O₃5H₂O haver baeen desolved per dm³ of solution. Find out Percentage of Na₂S₂O₃5H₂O. Mol mass of Na₂S₂O₃ = 248 (5)

(d) Crystallize benzoic acid by crystallization method. (5)

(e) Seprate mixture of various ink by paper chromatography. (5)