FEDRAL BOARD
CHEMISTRY
HSSC-I (2012)
SECTION-A 
NOTE:- Section-A is compulsory. All parts of this section are to be answered on the question paper itself. It should be completed in the first 25 minutes and handed over to the Centre Superintendent Deleting/overwriting is not allowed. Do not use lead pencil.

 Q NO.1. Circle the correct option i.e. A/B/C/D. Each part carries one mark.

• What is the formula of Sodium oxide if 0.69 g of Sodium combines with 0.24 g of Oxygen?
  
  A) NaO
  B) Na₂O
  C) NaO₂
  D) Na₂O₂
  
  
• Which of the following pairs of mixture can be separated by sublimation?
  
  A) Na₂SO₄ and NaCI
  B) Benzoic acid and H₂O
  c) Sand and Naphthlene
  D) Pb⁺⁺  and Cd⁺⁺

• The critical temperature of a gas

1. Depends on the critical pressure 
2. Does not depend on nature of gas
3. Is lower than inversion temperature
4. Is higher than inversion temperature

• HF is among the weakest halogen acid due to
  
  A) Strong polar bond between H₂ and F₂
  B) Electronegativity of Fluorine
  C) Smaller size of Fluorine          
  D) Hydrogen bonding

• Which of the following are lsomorphs?
  
  A) NaNO₃ and CaCO₃
  B) ZnSO₄ and NiSO₄
  C) NaF and MAO
  D) All of these

• The blue colour of water in sea is due to:
  
  A) Reflection of blue sky by sea water
  B) Reflection of blue light by impurities in sea water
  C) Scattering of blue light by H₂O molecules
  D) Absorption of other colours except blue by H₂O molecules

• An ionic compound will dissolve in water only if
  
  A) Hydration energy low and lattice energy high
  B) Hydration energy high and lattice energy low
  C) Hydration energy high and lattice energy very high
  D) Hydration energy and lattice energy low

• For any system the difference between enthalpy and internal energy can be expressed as:
  
  A) CP
  B) CV
  C) RT
  D) PV
  
  
• The specific rate constant for the forward and reverse reactions are 25 x 10^-2 and 5 x 10³ respectively. The equilibrium constant for the reaction A+B(Irreversible sign)C+D______________:
  
  A) 2.5x10^-6
  B) 5x10^-5
  C) 2x10^-4
  D) 4x10²

• Which of the following statements about the order of reaction is TRUE?
  
  A) The order of reaction can only be determined by experiment
  B) A second order reaction is always bimolecular
  C) The order of reaction must be a positive integer
  D) The order of reaction increases with increase in temperature

• One mg of solute per kilogram of solution is:
  
  A) 1 M
  B) 1 PPm
  C) 1 m
  D) 1% w/w
  
  
• If 5.85 g of NaCI are dissolved m 90 g of H₂O. the mole fraction of NaCI is
  
  A) 01
  B) 02
  C) 0.0196
  D) 0.01
  
  
• A compound decomposes with half life of 8 seconds and half life is independent of concentration. How much time is consumed to convert the concentration of 1/16th (one sixteenth) of its initial concentration?
  
  A) 32 s
  B) 24 s
  C) 40 s
  D) 14 s

• Standard reduction electrode potential of the three metals A. B and C are 0.5 v. —3.0 v and —1 2 v. respectively. The order of reducing power is___________:      
  
  A) B > C > A
  B) A > B > C
  C) C > B > A
  D) A > C > B

• Shape of ClO₃ is
  
  A) Triangular pyramidal
  B) Tetrahedral
  C) Triangular bipyramidal
  D) Triangular planer

• The properties which depend mainly on the arrangement of atoms in the molecule and to  a lesser extent on their number are called properties
  
  A) Colligative
  B) Constitutive
  C) Additive
  D) Chemical
  
  
• The temperature at which the solid and liquid phase of a substance coexists is called
  
  A) Consulate temperature
  B) Triple point
  C) Boiling point
  D) Freezing point

SECTION –B

Q.2:- Answer any FOURTEEN parts. The answer to each question should not exceed 5 to 6 lines:

• What volume of 27% (W/v) HC1, with a density of 1.14 g/cm³ is required to produce 10 0 g of Hydrogen by the following equation:
  Mg_(s) + 2HCI_(aq) ---→ MgCI_2(aq) + H_2(g
• Why H₂ and Helium are nearly ideal at room temperature and ordinary pressure but SO₂ is non-deal?
• 180 g of glucose and 342 g of sucrose have the same number of molecules
• But different number of atoms present in them. Justify the statement?
• Differentiate between Isomorphism and Polymorphism?
• Why is the lattice energy of NaCI greater than KCI which in turn is greater than KBr?
• BF₃, BCI₃ and AICI₃ are triangular planer molecule but NH₃, NF₃, and PCI₃ are triangular pyramids although in all these compounds the central atom is connected with three other atoms   
•  Calculate the radius of third (n=3) orbit of Hydrogen atom.What is the energy of an electron in this orbit?
•  Explain Hybridization in BF3.
  
• Calculate the heat of formation of C₃H₈ Propane from the following data:
  Heat of combustion of  C, H2 and C3H8 is 393 kjm-1 and -2213 kjm-1, respectively.    
• What are the optimum conditions of temperature, pressure and catalyst for obtaining maximum yield of products in the following industrial processes
             A) N _2(g) + 3H _2(g) (Irreversible sign) 2NH _3(g)
             B) 2SO _2(g) + O _2(g) (Irreversible sign) 2SO _3(g)

•  Explain why aqueous solution of CuSO₄, CH₃COONa and NaCI are acidic, basic and neutral respectively.
  
• Balance the following equations by ion-electron method in basic medium 
         A) CN^--- +MO^---₄ --→ CNO^--- MnO
         B) IO^---3 + ASO ^3-₃ --→ I^--- +ASO^3-₄
  
• How is power generated by using the fuel cell?
• Differentiate between Molecularity and Order of reaction.
• Why is it necessary to state the physical state of reactants and products in the thermochemical equations?
• What is common ion-effect? Give its two applications
• Differentiate between stationary phase and mobile phase
• What is the role of stationary phase in chromatography?
• Derive Graham’s law of diffusion from Kinetic Molecular theory.
• Differentiate between Continuous and Line spectrum .

SECTION - C

Note:- Attempt any TWO questions. All questions carry equal marks.

Q NO.3 
A) Derive an expression for the calculations of energy frequency and wave number of photon emitted when electron Jumps from n=1 to n=2 orbit .                
B) What is Absolute Zero?
C)Why is the Molecular orbital theory superior to valence bond and VSEPR theory?

 Q NO.4

1. Define Arrhenius equation.
2. Draw a complete fully labelled *Born-Haber" cycle for the formation of NaCI.
3. What is the pH of 10_-4 moles dm_-3 of HCI and Ba(OH)₂

 Q NO.5

      a.What is Planck's Quantum theory?
      b.Molar HCIO4 is available from the market The density of this solution is 1.54 gcm—3 What is the percentage by weight of HCIO₄?
      c.Describe the standard Hydrogen Electrode How will you use 'SHE' to measure the standard electrode potential of Zinc electrode?

CHEMISTRY HSSC-I (2012)
SECTION-A
PAPER-II
NOTE:- Section-A is compulsory. All parts of this section are to be answered on the question paper itself. It should be completed in the first 25 minutes and handed over to the Centre Superintendent Deleting/overwriting is not allowed. Do not use lead pencil.

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

• Water has the mass of 27 g. The number of water molecules is __________:
  
  A) 6.02x10²³
  B) 9.033x10²³
  C) 3.011x10²³
  D) 12.04x10²³
  
  
• Which of the following elements can NOT be analyzed directly by combustion analysis?
  
  A) Nitrogen
  B) Hydrogen
  C) Carbon
  D) Oxygen
  
  
• Which of the following substances is used as a decolourizing agent?
  
  A) Animal charcoal
  B) P₂O₅
  C) Silica gel
  D) None of these
  
  
• Which property of the gas is a state function?
  
  A)  Entropy
  B) Enthalpy
  C) Pressure
  D) All of these
  
  
• What happens when Copper electrode is coupled with Aluminium electrode in the galvanic cell?
  
  A) Oxidation takes place at Cu electrode
  B) Reduction takes place at Cu electrode
  C) Reduction takes place at Aluminium electrode
  D) None of these

• For the given value of oxidation state which is the oxidation state of Carbon in C₆H₁₂O₆?
  A) +6
  B) +12
  C) Zero
  D) -6

• An aqueous solution of water and ethanol may have vapour pressure  
  
  A) Equal to that of H₂O
  B) Equal to that of Ethanol
  C) More than that of water
  D) Less than that of water

• If uncertainty in position of electron is zero, then uncertainty in momentum would be          
  
  A) Zero
  B) infinite
  C) Less than zero
  D) h/2 π
  
  
• N₂ and O₂ are present in air but they do not react chemically at ordinary temperature and pressure because it is_________________________
  
  A) Non-spontaneous reaction
  B) Spontaneous reaction
  C) Reversible reaction
  D) Exothermic reaction
  
  
• The solubility of PbF₂ is 2.6 x10^-3 mol dm ^-3. Its solubility product will be         
  
  A) 7.0 x 10^-8
  B) 6.2 x 10^-8
  C) 8.0 x l0^-7
  D) 7. 8 x 10^-8
   
• Which of the following has the highest value of pH?
  
  A) 0.1 M NaOH
  B) Pure water
  C)Bread
  D)Rain water

• When a colourless, odourless gas was compressed, a whitish solid is formed. What is the gas?
  
  A) NH₃
  B) SO₂
  C)SO₃
  D)CO₂

• Dipole moment is the measure of polarity. Which of the following molecules is polar?
  
  A) CCI₄
  B) BF₃
  C)CF₄
  D)NF₃
  
  
• The reaction rate becomes four times by doubling the concentration of a reactant, then order with respect to that reactant is ____________?
  
  A) Zero order
  B) First order
  C)Second order
  D)Third order

• A certain ion has ground state configuration [Ar] 3d¹⁰This ion is __________:
  
  A) Cu²⁺
  B) Cu ⁺
  C)Zu⁺
  D)Cr³⁺

• In which crystal a ≠b ≠ c, α =β = Ү= 90° ?
  
  A) Cubic
  B) Triclinic
  C)Orthorhombic
  D)Hexagonal

• Dipole-dipole interactions are present in the
  
  A) Atoms of the Helium gas
  B) Molecules of CCI₄
  C)Molecules of solid l₂
  D)Molecules of NH₃

SECTION –B

Q.2:-

Answer any FOURTEEN parts. The answer to each question should not exceed 5 to 6 lines:    

• Hydrazine (N2H4) can be produced as follows. CINH₂ +₂NH₃→ N₂H₄+NH₄CI
• If 2.00 kg of chloral-amine (CI-NH₂) produces 946.0 g of hydrazine. Calculate the percentage yield of hydrazine.                   
• What are Isotopes/?
• Derive Boyle's law and Charles law from kinetic molecular theory.
• Why is Sodium softer than Copper, but both are very good electrical conductor?
• What is Artificial radioactivity? Write chemical equation for the production of proton and neutron.
• Calculate energy, frequency and wavelength of radiation emitted when electron drops from n=4 to n=2 for Hydrogen atom
• How does dipole-moment help us to predict the geometry of Triatomic molecule and Tetraatomic molecule?
• Differentiate between sigma and pi-bond by giving examples of HF and O₂.
• Calculate the Enthalpy change (∆H) for the reaction:      Image
• Write three definitions of Raoult's law.   
• Balance the following equations by oxidation number method:  Image
•  Zn can replace Cu from CuSO4 solution while Zn does not replace Mg from MgSO₄ solution Write cell reactions in support of your answer. Reduction potential of Zn = -0.76 v. Reduction potential of Mg = - 2 37 v   
• In the reaction of NO and H2 it was observed that equimolecular mixture of gases at 340.5 mm pressure was half changed in 102 seconds In another experiment with an 
• initial pressure 288 mm of Hg the reaction was half completed in 140 seconds.
• Calculate the order of reaction          
• Define Chromatography. What is the main difference between Absorption Chromatography and Partition Chromatography?
• Solubility is affected by temperature. Prove.
• The sum of the mole fractions of all the components is always equal to unity for any solution. Explain with reasons 
• What is meant by Activation of a catalyst and Poisoning of a catalyst?Give one example in each case 

SECTION - C

Note:-  Attempt any TWO questions. All questions carry equal marks.

Q NO.3

1. What is Dalton's law of Partial Pressure? How will you calculate partial pressure of a gas?
2. There is a mixture of H₂. He and CH₄ occupying a vessel of volume 13 dm³ at 37°C and pressure of 1 atm. The masses of H₂ and He are 0 8 g and 0.12 9. Respectively.
3.  Calculate the Partial Pressure of each gas in torr.  
     (I)Differentiate between Orbit and Orbital.

 Q NO.4

1. These species NH₂, NH₃ ant NH⁺₄ have bond angles of 105° ,107.5° and109 5° respectively Justify these values by drawing their structures according to VSEPR theory.
2. What are the drawbacks of Bohr's Atomic model?
3. Differentiate between Ideal and Non-ideal solutions 

Q NO.5 

       a. Derive Henderson’s equation
       b.What is Catalysis? Differentiate between Homogeneous and Heterogeneous catalysis.
       c.SHE acts as anode when connected with Cu electrode and as cathode when connected with Zn electrode Explain by writing cell reactions.