Question

Identify the acid which matches the following (i) to (v)

(i) The acid which is used in the preparation of a non- volatile acid

(ii) The acid that produces sugar charcoal from sugar

(iii) The acid which is prepared by catalytic oxidation of ammonia

(iv) The acid on mixing with Lead nitrate solution produces a white precipitate which is insoluble even on heating.

(v) The acid on mixing with Silver nitrate solution produces a white precipitate which is soluble in excess Ammonium hydroxide.

Answer 1

Part 1: Nitric acid:-

1. The acid is used in the preparation of a non-volatile acid - Nitric acid$\left({\mathrm{HNO}}_3\right)$.
2. It is a colourless liquid that produces red or yellow fumes.

Part 2: Conc. Sulphuric acid:-

1. The acid that produces sugar charcoal from sugar - conc. Sulphuric acid $\left({\mathrm{H}}_2{\mathrm{SO}}_4\right)$.
2. Sulphuric acid in concentrated form is a weak acid and a poor electrolyte.

Part 3: Nitric acid:-

1. The acid is prepared by catalytic oxidation of ammonia - Nitric acid $\left({\mathrm{HNO}}_3\right)$.
2. The Ostwald process is defined as the catalytic oxidation of ammonia to produce Nitric acid.
3. The reaction is $$\begin{gathered} \underset{\mathrm{Ammonia}}{4{\mathrm{NH}}_3\left(\mathrm{g}\right)}+\underset{\mathrm{Oxygen}}{5{\mathrm{O}}_2\left(\mathrm{g}\right)}\underset{500\mathrm{K},9\mathrm{bar}}{\overset{\mathrm{Pt}/\mathrm{Rh}\mathrm{catalyst}}{\to }}\underset{\mathrm{Nitric}\mathrm{oxide}}{4\mathrm{NO}\left(\mathrm{g}\right)}+\underset{\mathrm{Water}}{6{\mathrm{H}}_2\mathrm{O}\left(\mathrm{g}\right)} \\ \underset{\mathrm{Nitric}\mathrm{oxide}}{2\mathrm{NO}\left(\mathrm{g}\right)}+\underset{\mathrm{Oxygen}}{{\mathrm{O}}_2\left(\mathrm{g}\right)}\rightleftharpoons \underset{\mathrm{Nitrogen}\mathrm{dioxide}}{2{\mathrm{NO}}_2\left(\mathrm{g}\right)} \\ \underset{\mathrm{Nitrogen}\mathrm{dioxide}}{2{\mathrm{NO}}_2\left(\mathrm{g}\right)}+\underset{\mathrm{Water}}{{\mathrm{H}}_2\mathrm{O}\left(\mathrm{g}\right)}\to \underset{\mathrm{Nitric}\mathrm{acid}}{2{\mathrm{HNO}}_3\left(\mathrm{l}\right)}+\underset{\mathrm{Nitric}\mathrm{oxide}}{\mathrm{NO}\left(\mathrm{g}\right)} \end{gathered}$$

Part 4: Sulphuric acid:-

1. The acid on mixing with Lead nitrate solution produces a white precipitate which is insoluble even on heating is Sulphuric acid
2. The reaction is:-$$\begin{gathered} \mathrm{Pb}{\left({\mathrm{NO}}_3\right)}_2\left(\mathrm{aq}\right)+{\mathrm{H}}_2{\mathrm{SO}}_4\left(\mathrm{aq}\right)\to 2{\mathrm{HNO}}_3\left(\mathrm{aq}\right)+{\mathrm{PbSO}}_4\left(\mathrm{s}\right) \\ (\mathrm{Lead}\mathrm{nitrate})(\mathrm{Sulphuric}(\mathrm{Nitric}(\mathrm{Lead}\mathrm{sulphate}) \\ \mathrm{acid})\mathrm{acid}) \end{gathered}$$

Part 5: Hydrochloric acid:-

1. The acid on mixing with Silver nitrate solution produces a white precipitate which is soluble in excess Ammonium hydroxide is Hydrochloric acid.
2. The reaction is :- $$\begin{gathered} {\mathrm{AgNO}}_3\left(\mathrm{aq}\right)+\mathrm{HCl}\left(\mathrm{aq}\right)\to \mathrm{AgCl}\left(\mathrm{s}\right)+{\mathrm{HNO}}_3\left(\mathrm{aq}\right) \\ (\mathrm{Silver}\mathrm{nitrate})(\mathrm{Hydrochloric}(\mathrm{Silver}(\mathrm{Nitric}\mathrm{acid}) \\ \mathrm{acid})\mathrm{chloride}) \end{gathered}$$

Conclusion

(i) Nitric acid

(ii) Conc. Sulphuric acid

(iii) Nitric acid

(iv) Sulphuric acid

(v) Hydrochloric acid