Question

When ${\mathrm{NH}}_4\mathrm{OH}$ is dissolved in water it gives ${\mathrm{NH}}_4^{+}$ ion and ${\mathrm{OH}}^{-}$ ion. Is it a base or an alkali. Give reason.

Answer 1

Base and Alkali:

• Oxides or hydroxides of metals that react with the acid to form salts and water are called bases.
• Alkali is a chemical substance whose dissolution in water gives hydroxide ions $\left({\mathrm{OH}}^{-}\right)$.

Dissolution of Ammonium hydroxide in water:

• When ammonium hydroxide $\left({\mathrm{NH}}_4\mathrm{OH}\right)$ is dissolved in water, it gives ammonium $\left({\mathrm{NH}}_4^{+}\right)$ and hydroxide $\left({\mathrm{OH}}^{-}\right)$ ions.
• It is an alkali because when it gets dissolved in water, it furnishes hydroxide ion $\left({\mathrm{OH}}^{-}\right)$ ions.

Chemical Reaction:

• The chemical reaction is as follows:

${\mathrm{NH}}_4\mathrm{OH}\left(\mathrm{aq}\right)\to {\mathrm{NH}}_4^{+}\left(\mathrm{aq}\right)+{\mathrm{OH}}^{-}\left(\mathrm{aq}\right)$