100 mL of a solution contains 0.1 M $0.1{\mathrm{MNH}}_4\mathrm{OH}\text{ and }0.1{\mathrm{MNH}}_4\mathrm{Cl}$. The pH of the solution will not change on adding.

• A

  20 mL of 0.1 M ${\mathrm{NH}}_4\mathrm{OH}$ solution

• B

  $20 \mathrm{mL}\text{ of }0.1{\mathrm{MNH}}_4\mathrm{Cl}\text{ solution }$

• C

  $10 \mathrm{mL}\text{ of }0.1\mathrm{MNaOH}\text{ solution }$

• D

  l0 mL of distilled water