Question

Give one example each of the following:

Insoluble salt

Answer 1

1. Salts

Salts are the ionic compounds formed during the neutralization of acids and bases. They form cations and anions other than protons and hydroxide ions in solution. The nature of the salt formed depends on the ionic bonds between the ions of the respective acid and the base.

2. Insoluble salts

Salts that are insoluble in an aqueous solution are called insoluble salts. They form precipitate during the neutralization reaction. In these neutralization reactions, the aqueous solution of an acid and a base react to form a solid precipitate.

For example, Barium sulphate $\left({\mathrm{BaSO}}_4\right)$ formed from the neutralization of Sulphuric acid $\left({\mathrm{H}}_2{\mathrm{SO}}_4\right)$ and Barium hydroxide $\left[\mathrm{Ba}{\left(\mathrm{OH}\right)}_2\right]$ precipitates out during the reaction and is an insoluble salt. The neutralization is given as:

$$\begin{gathered} {\mathrm{H}}_2{\mathrm{SO}}_4\left(\mathrm{aq}\right)+\mathrm{Ba}{\left(\mathrm{OH}\right)}_2\left(\mathrm{aq}\right)\to {\mathrm{BaSO}}_4\left(\mathrm{s}\right)+2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right) \\ (\mathrm{Sulphuric}(\mathrm{Barium}(\mathrm{Barium}(\mathrm{Water}) \\ \mathrm{acid})\mathrm{hydroxide})\mathrm{sulphate}) \end{gathered}$$

Other examples of insoluble salts include Silver chloride $\left(\mathrm{AgCl}\right)$, Lead iodide $\left({\mathrm{PbI}}_2\right)$ , etc.