Question

The category of compounds which liberate ammonia on reaction with water:

• A. Nitrates
• B. Nitrites
• C. Nitrides
• D. None of these

Answer 1

The correct option is C

Nitrides

Explanation for correct answer:

• When water reacts with nitrides such as Magnesium nitrides, they produce ammonia.
• The reaction can be given as follows:

$$\begin{gathered} M{g}_3{N}_2\left(s\right)+6H_{2}O\left(l\right)\to 3Mg{\left(OH\right)}_2\left(s\right)+2N{H}_3\left(g\right) \\ MagnesiumnitrideWaterMagnesiumHydroxideAmmonia \end{gathered}$$

Explanation for incorrect answer:

• Nitrates in reaction with water will produce metal hydroxides and nitric acid.
• $$\begin{gathered} \mathrm{Mg}{\left({\mathrm{NO}}_3\right)}_2\left(\mathrm{aq}\right)+2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)\to 2{\mathrm{HNO}}_3\left(\mathrm{aq}\right)+\mathrm{Mg}{\left(\mathrm{OH}\right)}_2\left(\mathrm{s}\right) \\ \mathrm{Magnesium}\mathrm{Water}\mathrm{Nitric}\mathrm{acid}\mathrm{Magnesium} \\ \mathrm{nitrate}\mathrm{hydroxide} \end{gathered}$$
• Nitrites in reaction with water will produce metal hydroxides and nitrous acid.
• $$\begin{gathered} {\mathrm{NaNO}}_2\left(\mathrm{s}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)\to \mathrm{NaOH}\left(\mathrm{s}\right)+{\mathrm{HNO}}_2\left(\mathrm{l}\right) \\ \mathrm{Sodium}\mathrm{water}\mathrm{Sodium}\mathrm{Nitrous} \\ \mathrm{nitrite}\mathrm{hydroxide}\mathrm{acid} \end{gathered}$$
• Hence, options (A), (B) and (D) are incorrect.

Thus, the category of compounds that liberate ammonia on reaction with water is nitrides, option (C) is correct.