SAHIWAL BOARD
Chemistry
(Inter part 1)
Time : 20 min
Paper : I
Marks: 17

Note: You have four choices for each objective type question as A, 0, C and O. The choice which you think is correct; fill that circle in front of that question number with marker or pen. Cutting or filling two or more circles will result in zero mark in that question.

• The unit of rate constant in 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

• The cathodic reaction in the electrolysis of dil, fl,SO, with pt electrodes is
  

(a) Reduction
(b) oxidation  
(c) Both a and b         
(d) neighter a or b

• An aqueous solution of ethanol in water may have vapour pressure
  

(a) Equal to that of water       
(b) Equal to that of ethanol
(c) More than that of water  
(d) Less than that of water

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

(a) 3.0 
(b) 2.7
(c) 2.0 
(d) 1.5

• The law of mass action was given by:
  

(a) D.O Down and P.Waage
(b) Gay-Lussic and CM Gildberg
(c) C.M Gildberg and P.Waage
(d) Henderson and le-Chatelier

• If an endothermic reaction is allowed to take place very rapidly in the air, the temperature of the surrounding air
  

(a) Remains constant
(b) Increase      
(c) Decrease
(d) Remains unchanged

• Which of the following has zero dipole moment?
  

(a) NH           
(b) CHCI       
(c) H₂O           
(d) BF

• Which of the hydrogen halides has the highest percentage of ionic character
  

(a) HCL          
(b) HBr           
(c) HEv         
(d) HI

• The number of carbon atoms in 22.0 g of CO2 is:
  

(a) 3.01x1023  
(b) 6.02x1023 
(c) 3.01x1022  
(d) 6.02 x1022

Splitting of spectral lines when atoms are subjected to strong electric field is called

(a) Zeeman effect       
(b) Stark effect!
(c) Photoelectric effect          
(d) Compton effect

• Which of the following is a pseudo solid
  

(a) CaF₂              
(b) Glass         
(c) NaCI         
(d) All

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

(a) Intermolecular hydrogen bonding          
(b) Ion-dipole interactin
(c) Instantaneous dipole         
(d) All of the above

• The spreading of fragrance of a rose or scent in air is due to:
  

(a) Effusion    
(b) Diffusion 
(c) Osmosis    
(d) Evaporation

• Pressure remain 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) 546 K        
(d) 273 K

• Solvent extraction is an equilibrium process and is controlled by
  

(a) Law of mass action           
(b) The amount of solvent used
(c) Distribution law                
(d) The amount of solute

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

(a) 2.24 dm3   
(b) 22.4 dm3   
(c) 1.12 dm3   
(d) 1l2 cm3

• The mass of one mole of electron is:
  

(a) 1.008 mg   
(b) 0.55 mg   
(c) 0.184 mg   
(d) 1.673 mg

SAHIWAL BOARD
Chemistry
(Inter part - I)
Time : 3.10 hours
Paper-I
(Session 2013-2015)
Marks : 83

2. Write short answers to any eight parts. (8x 2 =16 )

• Define pH and pOH,
  
• Prove that pKa+pKb= 14 at 25°C
• Define Le-Chatelier's principle.
• Define system and surrounding with suitable example.
• Describe that burning of candle is a spontaneous process.
  
• Write two faulty assumptions of kinetic molecular theory of gasses.
  
• Calculate the value of gas constant ‘R’ in SI units.
  
• How mixture of NH₄Cl and NaCI can be separated?
  
• Why N₂ and CO have the same number of protons, electrons and nutrons.
  
• Define distribution law.
  
• Calculate the mass in grams of 10-3 moles of water.
  
• Differentiate between ion and molecular ion.
  

3. Answer briefly any eight parts from the followings:  (8x2 16)

• What are London Dispersion forces.
• Vacuum distillation can be used to avoid decomposition of sensitive liquid. Why?
• Define Polymorphism and Isomorphism. Give one example of each.
• Justify that diamond is non-conductor of electricity.
• What particles are formed by the decay of free neutron? Write balanced equation.
• Define (a) atomic absorption spectrum     (b) atomic emission spectrum.
• Give the electronic configuration of an element having atomic number 29.
• Calculate the wave number of photon, when the electron jumps form n=5 to n=2.
• Why the atomic radius decreases along period and increases along group?
• Why sigma bond is stronger than Pi-bond?
• Why helium gas do not exist in diatomic state?
• What is paramagnetic character? Give the reason for paramagnetic character of oxygen.

4. Write short answers to any six parts. (6x 2 =12 )

• Define percentage weight / weight. Give an example.
• Aqueous solution of CuSO₄ is acidic in nature. Justify it.
• Calculate the oxidation number of manganese in KMnO₄
• A porous plate or salt bridge is not required in lead storage cell. Explain it.
• How does impure copper can be purified by electrolytic process?
• Define Homogeneous Catalysis and give an example.
• A Cataqlyst is specific in its action. Briefly describe it.
• what is Discontinuous Solubility Curve?
• what is Autocatalyst? Give an example.

SECTION II
Note: Attempt any three (3) questions. (34=24)

Question#5
(a) What are the molecular solids? Give examples and explain their properties.
(b) A mixture of two liquids hydrazine N₂H₄ and N₂O₄ are used in rockets. They produce N₂ and water vapours. How many grams of N₂ gas will be formed by reacting 100 g of N₂H₄, and 200 g of N₂O₄.

Question#6
(a) How volume and pressure were corrected by Vander Waals?
(b) Discuss magnetic and spin quantum numbers.

Question#7
(a) Explain important points of molecular orbit theory and draw structure of - nitrogen (N₂) molecule accordingto this theory.
(b) Define the following with examples:
(i) System       
(ii) Non-spontaneous reactions
(iii) Surroundings       
(iv) Endothermic reactions

Question#8
(a) Explain any four characteristics of a catalyst.
(b) Benzoic acid C₃H₅COOH is a weak mono-basic acid (Ka . 6.4 x 10-5 moldm-3) What is the PH of a solution containing 7.32 g of sodium benzoate in one zim-3of 0.02 mole dm-3 mold-3 benzoic acid?

Question#9
(a) Describe the method to determine the boiling point elevation of a solution.
(b) Explain the construction and working of fuel cell.