At a certain temperature, 2HI $\rightleftharpoons$H₂ +I₂ only 50% HI is dissociated at equilibrium. The equilibrium constant is:

1. 1.0                     

2. 3.0                 

3. 0.5               

4. 0.25

A solution of FeCl₃ in water acts as acidic due to:

1. Acidic impurities                         

2. Ionization

3. Hydrolysis of Fe³⁺                       

4. Dissociation

Which of the following solution does not act as buffer?

1. H₃PO₄ + NaH₂PO₄

2. Na₂CO₃ + H₂CO₃

3. HCl + NH₄Cl

4. CH₃COOH + CH₃COONa

Which equilibrium can be described as Lewis acid-base reaction but not Bronsted acid-base reaction?

1. H₂O + CH₃COOH$\rightleftharpoons$H₃O⁺ + CH₃COO^-

2. 2NH₃ + H₂SO₄ $\rightleftharpoons$$2{\mathrm{NH}}_4^{+}$ + ${\mathrm{SO}}_4^{2-}$

3. NH₃ + CH₃COOH $\rightleftharpoons$${\mathrm{NH}}_4^{+}$ + CH₃COO^-

4. [Cu(H₂O)₄]²⁺ + 4NH₃ $\rightleftharpoons$ [Cu(NH₃)₄]²⁺ + 4H₂O

In the reaction, PCl₅ $\rightleftharpoons$PCl₃ + Cl₂, the amounts of PCl₅, PCl_3, and Cl₂ at equilibrium are 2 moles each and the total pressure is 3 atm. The equilibrium constant K_p is: 

1. 1.0 atm                                       

2. 2.0 atm

3. 3.0 atm                                       

4. 6.0 atm

An aqueous solution of hydrogen sulphide shows the equilibrium,

           H₂S $\rightleftharpoons$H⁺ + HS^-

If dilute hydrochloic acid is added to an aqueous solution of hydrogen sulphide without any change in temperature, then:

1. the equilibrium constant will change

2. the concentration of HS^- will increase

3. the concentration of undissociated hydrogen sulphide will decrease

4. the concentration of HS^- will decrease

When HCl gas is passed through a saturated solution of common salt, pure NaCl is precipitated because:

1. the impurities dissolve in HCl

2. HCl is highly soluble in H₂O

3. the product of [Na⁺] and [Cl^-] exceeds the solubility product of NaCl

4. the solubility product of NaCl is lowered by the chloride ion from aqueous HCl

The aqueous solution of a salt is alkaline. This shows that salt is made from:

1. a strong acid and strong base

2. a strong acid and weak base

3. a weak acid and weak base

4. a weak acid and strong base

40% of a racemic mixture of 0.2 moles of N₂ and 0.6 moles of H₂ react to give NH₃ according to the equation, N₂ (g) + H₂(g)$\rightleftharpoons$2NH₃ (g) at constant temperature and pressure. Then the ratio of the final volume to the initial volume of gases is:

1. 4:5                       

2. 5:4

3. 7:10                     

4. 8:5

On addition of inert gas at constant volume to the reaction, N₂ + 3H₂$\rightleftharpoons$2NH₃ at  equilibrium:

1. the reaction halts

2. forward reaction is favored

3. the reaction remains unaffected

4. backward reaction is favored