FEDERAL BOARD 2017
PAPER CHEMISTRY PART-1
Time: 20 MM.(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.

• Which one of the following metal cannot displace H₂ from H₂O ?
  

1. Cu
   
2. Na
   
3. K
   
4. Ca

• The number of covalent bonds present in 8 g CH₄ are:
  

1. 1.204 x 10²⁴
   
2. 3.01 x 10²³
   
3. 6.02 x 10²³
   
4. 6.02 x 10²⁴

• Paschen series of r spectral lines is produced due to transition of electrons from higher orbit to the:
  

1. 4^th orbit
   
2. 1^st orbit
   
3. 2 ^nd orbit
   
4. 3 ^rd orbit

• Which set of quantum numbers is NOT valid for an electron?
  

1. n = 3, l = 2, m = -2
   
2. n = 1, l = 1, m = 0
   
3. n = 2, l = 0, m = 0
   
4. n = 3, 1 = 1, m = -1

• The central atom is sp2 hybridized in:
  

1. CH₄
   
2. BeCl₂
   
3. BF₃
   
4. H ₂O

• Which one of the following has greater bond energy?
  

1. N≡ N
   
2. C≡0
   
3. C≡ N
   
4. C ≡ C

• Which one of the following gases possesses lowest density?
  

1. CH₄
   
2. CO₂
   
3. N₂
   
4. NH₃

• If both the pressure and temperature of a gas are doubled, the volume will;
  

1. Remain same
   
2. Become double
   
3. Increase four times
   
4. Become half

• The boiling points of NH₃, H₂O and HF decrease in the order;
  

1. HF > NH₃ > H₂0
   
2. H₂0 > NH_{3> HF}
   
3. H₂0 > HF > NH₃
   
4. HF > H₂0 > NH₃

• The existence of two compounds in the same crystalline form is known as:
  

1. Allotropy
   
2. Anisotropy
   
3. Isomorphism
   
4. Polymorphism

• In the reaction N₂0₄⇔2N0₃H = +57.2 kj the equilibrium will be shifted in forward direction by;
  

1. Increasing the concentration of NO₂
   
2. Increasing the temperature
   
3. Increasing the pressure
   
4. Decreasing the volume

• Which salt will from acidic solution in water?
  

1. K₂CO₃
   
2. KCI
   
3. NaBr
   
4. NH₄Cl

• The order of enzyme catalyzed reaction is:
  

1. 3
   
2. 0
   
3. 1
   
4. 2

• The bulling point of 0.1 molal solution of glucose in water is;
  

1. 105.2 °C
   
2. 100.50 °C
   
3. 100.052 °C
   
4. 101.86 °C

• 18 g glucose is dissolved in 180 g water. The relative lowering in vapour pressure is;
  

1. 0.001
   
2. 10
   
3. 1.8
   
4. 0.01

• The standard enthalpy of formation is zero for:
  

1. C₆H₁₂ O₆
   
2. 0₂
   
3. H₂0
   
4. NaCl

• Once coulomb is the charge carried by;
  

1. 9.11 x 10²³ electrons
   
2. 6.25 x 10 ¹⁸ electrons
   
3. 1. 602 x 10 ¹⁹ electrons
   
4. 6.02 x 10 ²³ electrons

FEDERAL BOARD 2017
PAPER CHEMISTRY PART-1
Time: 3:10 Hours (Subjective Part)Marks: 83

Section-B

Q.2 Answer any SEVEN parts. All parts carry equal marks.

1. One mole of H₂S0₄ should completely react with two moles of NaOH. How does Avogadro's number help to explain it?
   
2. Calculate the radius of first orbit of Hydrogen atom and Helium ion. Which one
   
3. has smaller radius? Give reason.
   
4. Describe the reason for the production of X—rays.
   
5. Draw the molecular orbital diagram for F₂ and calculate its bond order.
   
6. State and explain Joule - Thomson effect.
   
   1. a. State Graham's law.
      
   2. b. Determine the molar mass of a gas which diffuses four times faster as compared to S0₂ gas.
      
7. Calculate the bond energy of HBr. Bond energy of H₂ is 436 kj/mol and that of Br₂ is 193 kj/mol.
   
8. Explain why?
   
   1. a. Evaporation is a cooling process.
      
   2. b. C₆H₁₄ is a liquid whereas C₂ H₆ is a gas.
      
9. Write any three differences between molecular and metallic solids.
   
10. What is absolute zero? How will you derive it from Charles' law?

Section-C

 

Q.3 Answer any SEVEN parts. All parts carry equal marks.

1. Describe the effect of increase in pressure and temperature on the following reaction at equilibrium: 2S0_2(g) 0_2(g).  2S0_3(g) H = -198 Kj
   
   1. a. What is a precipitation reaction?
      
   2. b. How will you predict the formation of precipitates when two solutions are mixed together?
      
2. What is levelling effect? Describe giving an example.
   
3. Write down any three applications of buffer solutions.
   
   1. a. For the reaction N0₂ + C0 NO + CO₂ Rate = K [NO₂]₂ write down the mechanism.
      
   2. b. What will happen if the concentration of CO is increased three times in the above reaction? Justify your answer.
      
4. What is Arrhenius equation? How this equation describes the effect of increase in temperature on the rate constant and rate of a reaction?
   
5. Concentration of H₂SO₄ is 98% w/w. Its density is 1.84 / cm³. Calculate the molarity and molality of this solution.
   
6. Define Osmotic pressure, Colloids, and molal Freezing point Depression constant.
   
7. What is Calorimetry? Briefly describe, its types.
   
8. Describe, the rusting of iron,  giving the reactions taking place during the process.

Section-D

NOTE: Attempt any TWO questions. All questions carry equal marks.

Q. 4

1. Define hybridization. Name its types? Explain the structure of ethyne on the basis of hybridization.
   
2. Derive a relationship for total energy of electron present in nth orbit of hydrogen atom.

Q.5

1. a. Describe the quantitative aspect of elevation in boiling point.
   
2. (b) What is Born Haber cycle? Draw a labelled Born-Haber cycle for the formation of NaCI.

Q.6

1. a. Differentiate between limiting and non-limiting reactants. Calculate the mass of NH₃ produced when 100 g Ca (0H)₂ is reacted with 100 g NH₄
   ClCa(0H)₂ + 2NH₄C1  CaCl₂ + 2NH₃ + 2H₂0.
   
2. b. Describe the construction and working of an ordinary dry cell and alkaline dry cell, giving the reactions taking place at anode and cathode.