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%

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

Given, HF + H₂O$\stackrel{K_{\mathit{a}}}{\to }$H₃O⁺ + F^-

          F^- + H₂O $\stackrel{K_b}{\to }$HF + OH^-

which relation is correct?

1. K_b =K_w                       

2. K_b =1/K_w 

3. K_a x K_b =K_w                 

4.  K_a/K_b = K_w 

The concentration of [H⁺] and concentration of [OH^-] of a 0.1M aqueous solution of 2% ionised weak monobasic acid is                                                                    

[ionic product of water = 1x 10^-14]

1. 0.02x10^-3 M and 5x10^-11 M

2. 1x10^-3 M and 3x10^-11 M

3. 2x10^-3 M and 5x10^-12 M

4. 3x10^-2 M and 4x10^-13 M

Aqueous solution of acetic acid contains                                                   

1. CH₃COO^- and H⁺

2. CH₃COO^-, H₃O⁺ and CH₃COOH

3. CH₃COO^-, H₃O⁺ and H⁺

4. CH₃COOH, CH₃COO^- and H⁺

An aqueous solution of hydrogen sulphide shows the equilibrium,

           H₂S $\rightleftharpoons$H⁺ + HS^-

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

The following equilibrium exists in an aqueous solution 

CH₃COOH $\rightleftharpoons$H⁺ + CH₃COO^- . If dilute HCl is added to this solution:

1. the equilibrium constant will increase

2. the equilibrium constant will decrease

3. acetate ion concentration will increase

4. acetate ion concentration will decrease

In the following reaction

${\mathrm{HC}}_2{\mathrm{O}}_4^{-} + {\mathrm{PO}}_4^{3-} \rightleftharpoons {\mathrm{HPO}}_4^{2-} + {\mathrm{C}}_2{\mathrm{O}}_4^{2-}$ 

Which are the two Bronsted bases ?

1. ${\mathrm{H}}_2{\mathrm{C}}_2{\mathrm{O}}_4^{-} \mathrm{and} {\mathrm{PO}}_4^{3-}$

2. ${\mathrm{HPO}}_4^{2-} \mathrm{and} {\mathrm{C}}_2{\mathrm{O}}_4^{2-}$

3. ${\mathrm{H}}_2{\mathrm{C}}_2{\mathrm{O}}_4^{-} \mathrm{and} {\mathrm{HPO}}_4^{-2}$

4. ${\mathrm{PO}}_4^{3-} \mathrm{and} {\mathrm{C}}_2{\mathrm{O}}_4^{2-}$

Ostwald dilution law for weak electrolyte HA can be given as

$\left(1\right) {\mathrm{K}}_{\mathrm{a}}=\frac{{\mathrm{C\alpha }}^2}{(1-\mathrm{\alpha })}$
$\left(2\right) \mathrm{Ka} = {\mathrm{C\alpha }}^2 \mathrm{if} \mathrm{\alpha }\to 0$
$\left(3\right) {\mathrm{K}}_{\mathrm{a}} = \frac{{\mathrm{C\lambda }}^2}{{\mathrm{\lambda }}^2({\mathrm{\lambda }}^2-\mathrm{\lambda })}$
$\left(4\right) \mathrm{All} \mathrm{of} \mathrm{the} \mathrm{above}$

The molecule that is least likely to behave as Lewis base is: 

1. NH₃

2. BF₃

3. OH^-

4. H₂O