Question

Name a gas which dissolves in water to give alkaline solution.

Answer 1

1. A basic compound/ base on dissolving in water forms a basic solution or a alkaline solution.
2. Ammonia (${\mathbf{NH}}_{\mathbf{3}}$) is considered a weak base which on dissolving in water forms an Ammonium hydroxide (${\mathbf{NH}}_{\mathbf{4}}\mathbf{OH}$) solution.
3. Ammonium hydroxide (${\mathbf{NH}}_{\mathbf{4}}\mathbf{OH}$) is a weak base which forms an alkaline solution.
4. The reaction is shown below.
   $$\begin{gathered} {\mathrm{NH}}_3\left(\mathrm{g}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)\to {\mathrm{NH}}_4\mathrm{OH}\left(\mathrm{aq}\right) \\ \mathrm{Ammonia}\mathrm{Ammonium}\mathrm{hydroxide} \end{gathered}$$
5. Therefore, a gas which dissolves in water to give alkaline solution is Ammonia (${\mathbf{NH}}_{\mathbf{3}}$).