Fedral Board Chemistry 2013
PART-I

1 Circle the correct option. 17

• Which of the following has least mass?

a) 1 mol of 0,
b) 7 gram of Ag
c) 3.01 x 1023 atoms of C
d) 2 gram atoms of N

• The Partial pressure of 11, in a flask containing 2 grams of II, and 16 grams of 0, is

a) 1
b) 2
c) 1
d) 4

• Boiling point of solution is independent of

a) Nature of Solvent
b) Amount of solution
c) Pressure
d) Concentration of solution

• n + 1 value for an orbital 'A' is 2 + 1 = 3 while for 'B' is 3 + (1 = 3 . The energy order is

a) A>B
b) B>A
c) A = B
d) Cannot be predicted

• For the reaction N₂+3H, <>2NH., AH = —92KJ mol ,which of the following gives the greatest yield of N11,

a) Adding a catalyst
b) Decreasing the temperature and pressure
c) Decreasing the temperature & increasing the pressure
d) Increasing the temperature & decreasing the pressure

• Joule Thomson expansion of an ideal gas produces

a) Heatirig
b) Cooling
c) Gas liquefies
d) No change in temperature

• The frequency of X-rays having wavelength of 4A (Angstrom) is

a) 1.33 x 10" Hz
b) 2x 10'8 Hz
c) 7.5 x 10¹⁷ Hz
d) 2.6 x 10 Hz

• A solution of glucose is 10% wlv. The volume in which one mol of it is dissolved will be

a) 1dm³
b) 1.8dm³
c) 10dm
d) 18dm

• If the energy of activated complex lies close to the energy of reactants, it means that the reaction is

a) Slow
b) Fast
c) Reaction does not take place
d) Endothermic

• After three half lives of a reaction, the % fraction of the amount left is

a) 75%
b) 50°k
c) 12.5%
d) 25%

• For the reaction 112+ 1, c> 2111 the value of Kc = 64 . If the volume of the container is reduced to one half of its original volume. the value of K is

a) 48
b) 16
c) 64
d) 32

• Which of the following solutes will depress the freezing point of water the least. if one mole of each is added?

a) NaCl
b) Cacl₂
c) C₆H1₂O₆
d) ALCL₃

• How many moles of oxygen atoms are there in 0.5 moles of Ca( C/O,

a) 3 moles
b) 6 moles
c) 0.5 moles
d) 1 mole

• Which metal will dissolve in galvanic cell containing copper and silver electrodes' (rH Cu =11.341=-0,8111')

a) Copper
b) Silver
c) Both A and B
d) None

• What is the unit cell with crystallographic dimensions a=b= c and q=B=r=90?

a) Cubic
b) Tetragonal
c) Monoclinic
d) Rhombic

• For a chemical reaction CH₃C00H <> CH₃COO+H........

a) All <zero
b) All =0
c) All > zero
d) All = Negative

• During the electrolysis of aqueous solution of NaCl using inert electrodes

a) H2, liberates at cathode
b) (Cl2, liberates at cathode
c) Na deposits at anode
d) 0, evolves at anode .

2. Attempt any Fourteen parts. 42

The answer to each part should not exceed 5 to 6 lines.

• A sample of /1/0, contains 5.4 x 1021 CI- ions. Calculate:
  a) Number of Formula units of .11/03
  b) Number of AI'' ions in the sample
  c) Mass of the sample ( = 27 ; 0 = 35.5)
• a) The rate of filtration can be increased by using Fluted Filter Paper. Why?
  b) During crystallization process, why do some crystals appear coloured? How will the undesirable colours of crystals be removed?
• a) State Avogadro's Law.
  b) Calculate the number of molecules in 1050•nj of (-0, at 25 "C and 800 mm Hg pressure).
• a) Define Molar heat of Vaporization and Molar heat of Sublimation.
  b) Explain why heat of sublimation of a substance is greater than heat of vaporization.
• Why is it impossible to determine both the position as well as momentum of an electron in an atom simultaneously?
• a) What is lionization energy?Why is the 1" I.E <2"" I.E and so on?
  b) Why does the I.E increase along the period?
• For the processes taking place at constant pressure.prove All = y,,
• Calculate the value of hp for the synthesis of V/according to the equation.+ 3H 2NH, he = 6 x 10) at 500 "C
• a) Define Molality.
  b) What is the Molality of 10% wiw \a(1 siotcON
• a) What is Eiectrode Potential? ,,t,ja.kJ
  b) Standara electrode potential valttes are given:
  Zn = +0.7 61' ; / Crt = 0.3417
  Calculate emf of the cell.Also write the complete cell equation.
• a) What is the Order of Reaction?
  b) A study of kinetics of a reaction I + B -› Product.
• Given the following data:
  

  Exp#	[I]	[B]	Initial rate
  	1.00	015	4.2 x 10
  II	2.00	0.15	8.4 x 10
  III	1.00	0.20	5.6 x 104

  Calculate the order of reaction.
• a) Define Salt Hydrolysis.
  b) Why is the aqueous solution of NaCI neutral and that of NH ,CI acidic?
• Balance the Redox Equation by Ion Electron method in acidic medium: Cr₂0₂ +CI --+ Cr') +0₂
• The solubility of Mg1; is 7.6 x 10-1 gdm-j at 25 °C. Calculate its solubility product (Mg = 24; F =19)
• a) What is Enthalpy?
  b) Under what conditions All = AE
• Give reasons: a) The dipole moment of CO, and CS, is zero, but that of SO₂ is 1.62 D.
  b) Pi bonds are more diffused than sigma bonds.
• Calculate the Energy, Frequency and Wavelength of radiationemitted when electron jumps from n--,4 to n7-2 f hydrogen atom.
• a) Why do t boiling points of noble gases increase down the group?
  b) Freshly cut surface of the metal is shiny. Why?
• Verify Graham's Law of diffusion from kinetic gas equation.

 Attempt any Two questions. 26

3. a) i) Define Stoichiometry. What assumptions are made while performing Stoichiometric calculations?
ii) 50 g each of NH,0 and Ca(O11)₂ reacted together according to the equation: NO₂O₃ +Ca(O11)₂—>₂N11 ., +CaC1₂ +2H,0.
Calculate the mass of MI, formed.(N =14 ; C/ = 3 5.5 ; Ca= 40)
b) i) Using kinetic gas equation PI,' = I mA' e^-3 workout an expression which relates the average kinetic energy of the gas molecules to the absolute temperature.
ii) Why is the volume of a gas generally expressed in g dm 4 rather than g cm-3?

4 a) i) Give the main postulates of VSEPR theory.
ii) Explain the structure and geometry of BeCl,and SnO, on the basis of VSEPR theory.
b) What is Atomic Orbital Hybridization?Explain hybridization in Ethene and Water.

5 a) i) What are Buffers? How do the buffers act?
ii) What is the pH of a solution containing 7.2 g of sodium benzoate C611,COONa in one dm' of 0.02 M benzoic acid C, 11,COOH.(Ka = 6.4 x 1 0-5).
b) How does the Arrhenius equation help to determine the energy of activation?