The conjugate base of H₃BO₃ is:

1. $\mathrm{B}(\mathrm{OH}{)}_4^{-}$                                     

2. ${\mathrm{H}}_2{\mathrm{BO}}_3^{-}$

3. ${\mathrm{HBO}}_3^{2-}$                                       

4. ${\mathrm{H}}_4{\mathrm{BO}}_3^{+}$

The degree of dissociation of PCl₅ ($\mathrm{\alpha }$) obeying the equilibrium,

PCl₅ (g) $\rightleftharpoons$ PCl₃ (g) + Cl₂ (g), is approximately related to the pressure at equilibrium by:

1. $\alpha \propto P$                                         

2.  $\alpha \propto 1/\sqrt{P}$

3.  $\alpha \propto 1/{\mathrm{P}}^2$                                   

4.  $\alpha \propto 1/P^4$

In a system: $A\left(\mathrm{s}\right)\stackrel{ }{\rightleftharpoons }2B\left(\mathrm{g}\right) + 3C\left(\mathrm{g}\right).$ If the concentration of C at eqilibrium is increased by a factor 2, it will cause the eqilibrium concentration of B to change to:

1. two times of its original value

2. one half of its original value

3. 2$\sqrt{2}$ times of its original value

4. $\frac{1}{2\sqrt{2}}$ times of its original value

For the reaction:

 CO(g) + $\frac{1}{2}$O₂(g) $\rightleftharpoons$CO₂(g), K_p/K_c is:

1. RT              

2. (RT)^-1               

3. (RT)^-1/2               

4. (RT)^1/2

 A weak acid, HA has a K_a of 1.00 x 10-5. If 0.100 mole of this acid is dissolved in one litre of water, the percentage of acid dissociated at equibrium is closest to

1. 99.9%                           

2. 1.00%                      

3. 99.9%                             

4. 0.100%

If little heat is added to ice $\rightleftharpoons$ liquid equilibrium in a sealed container, then:

1. Pressure will rise                           

2. Temperature will rise

3. Temperature will fall                       

4. No change in P and T

In the equilibrium,

2SO₂(g) + O₂ (g) $\rightleftharpoons$2SO₃(g), the partial pressure of SO₂, O₂ and SO₃ are 0.662, 0.101 and 0.331 atm respectively. What should be the partial pressure of oxygen so that the equilibrium concentration of SO₂ and SO₃ are equal.

1. 0.4 atm                   

2. 1.0 atm

3. 0.8 atm                   

4. 0.25 atm

Ionisation constant of CH₃COOH is 1.7 X 10^-5 and concentration of H⁺ ions is 3.4 X 10^-4.Then, find out initial concentration of CH₃COOH molecules.            

1. 3.4 X 10^-4 

2. 3.4 X 10^-3

3. 6.8 X 10^-4

4. 6.8 X 10^-3

The formation of phosgene is represented as,

            CO + Cl₂ $\rightleftharpoons$COCl₂

The reaction is carried out in 500 mL flask. At equilibrium o.3 mole of phosgene, 0.1 mole of CO and 0.1 mole of Cl₂ are present. The equilibrium constant of the reaction is:

1. 30                     

2. 15

3. 5                       

4. 3

The decreasing order of strength of the bases,

OH^-, N${\mathrm{H}}_2^{-}$, H-C$\equiv$C^- and CH₃-C${\mathrm{H}}_2^{-}$ is:

1. CH₃-C${\mathrm{H}}_2^{-}$>N${\mathrm{H}}_2^{-}$> H-C$\equiv$C^->OH^-

2. H-C$\equiv$C^-> CH₃-C${\mathrm{H}}_2^{-}$>N${\mathrm{H}}_2^{-}$>OH^-

3. OH^->N${\mathrm{H}}_2^{-}$>H-C$\equiv$C^->CH₃-C${\mathrm{H}}_2^{-}$

4. N${\mathrm{H}}_2^{-}$>H-C$\equiv$C^->OH^->CH₃-C${\mathrm{H}}_2^{-}$