At 25°C, the pH of a solution containing 0.10 M sodium acetate and 0.03 M acetic acid will be:

[pK_a value of ${\mathrm{CH}}_3\mathrm{COOH}=4.57$]-

1. 3.24

2. 4.59

3. 5.09

4. 6.67

The ratio of the concentration of salt and acid for preparing a buffer solution of pH 6 by mixing sodium acetate and acetic acid will be: (K_a=10^-5)

1. 1:10

2. 10:1

3. 100:1

4. 1:100

The pH of a solution made by mixing 50 mL of 0.01 M barium hydroxide solution with 50 mL of H₂O is

The solution with pH value close to 1.0 among the following is:

The pH of a 0.05 M aqueous solution of diethylamine is 12. Its K_b value will be:

1. $2\times {10}^{-3}$

2. $2.5\times {10}^{-3}$

3. $3\times {10}^{-3}$

4. $4.5\times {10}^{-3}$

K_a for HCN is $5\times {10}^{-10}$ at $25°\mathrm{C}$. For maintaining a constant pH of 9, the volume of 5 M KCN solution required to be added to 10 mL of 2 M HCN solution is-

1. 2 mL

2. 3 mL

3. 4.2 mL

4. 5.6 mL

Which of the following compounds is in the correct sequence in terms of relative basic strength?

1. ${\mathrm{C}}_2{\mathrm{H}}_5{\mathrm{O}}^{-}>\mathrm{CH}\equiv {\mathrm{C}}^{-}>{\mathrm{OH}}^{-}$

2. $\mathrm{CH}\equiv {\mathrm{C}}^{-}{>}^{-}\mathrm{OH}>{\mathrm{C}}_2{\mathrm{H}}_5{\mathrm{O}}^{-}$

3. $\mathrm{CH}\equiv {\mathrm{C}}^{-}>{\mathrm{C}}_2{\mathrm{H}}_5{\mathrm{O}}^{-}>{\mathrm{OH}}^{-}$

4. ${\mathrm{C}}_2{\mathrm{H}}_5{\mathrm{O}}^{-}>{\mathrm{OH}}^{-}>\mathrm{CH}\equiv {\mathrm{C}}^{-}$

The concentration of CH₃COOH that will have the same [H⁺] as obtained from 10^-2 M HCOOH, is-

$\left(\mathrm{Ka}\right({\mathrm{CH}}_3\mathrm{COOH})={10}^{-5},$ $\mathrm{Ka}\left(\mathrm{HCOOH}\right)={10}^{-4})$

1. 10 M

2. 5 M

3. 10^-1 M

4. 6 M

When NH₄Cl is added to an aqueous solution of NH₄OH, then

1. Concentration of $\left[{\mathrm{OH}}^{-}\right]$ ions decreases.

2. Concentration of $\left[{\mathrm{OH}}^{-}\right]$ ions increases.

3. Concentration of $\left[{\mathrm{NH}}_4^{+}\right]$ ions as well as concentration $\left[{\mathrm{OH}}^{-}\right]$ ions increase.

4. Concentration of $\left[{\mathrm{NH}}_4^{+}\right]$ ions decreases.

A solution of benzoic acid (a weak monobasic acid) is titrated with NaOH. The pH of the solution is 4.2 when half of the acid is neutralized. The dissociation constant of the acid will be:

1. $3.2\times {10}^{-5}$

2. $6.42\times {10}^{-4}$

3. $6.31\times {10}^{-5}$

4. $8.7\times {10}^{-8}$