Question

Identify the following substance that is underlined: A dilute mineral acid which forms a white precipitate when treated with barium chloride solution.

Answer 1

• A dilute mineral acid that forms a white precipitate when treated with barium chloride solution is dilute sulphuric acid.
• Balanced chemical equation:

$\underset{\mathrm{Barium}\mathrm{chloride}}{{\mathrm{BaCl}}_2\left(\mathrm{aq}\right)}+\underset{\mathrm{Sulphuric}\mathrm{acid}}{{\mathrm{H}}_2{\mathrm{SO}}_4\left(\mathrm{aq}\right)}\to \underset{\mathrm{Barium}\mathrm{sulphate}}{{\mathrm{BaSO}}_4\left(\mathrm{s}\right)\downarrow }+\underset{\mathrm{Hydrochloric}\mathrm{acid}}{2\mathrm{HCl}\left(\mathrm{aq}\right)}$

• During this reaction, a white precipitate of barium sulphate is formed.
• It is a double displacement reaction because the exchange of ions takes place between both reactants.

Hence, A dilute mineral acid that forms a white precipitate when treated with barium chloride solution is dilute sulphuric acid $\mathbf{\left(}{\mathbf{H}}_{\mathbf{2}}{\mathbf{SO}}_{\mathbf{4}}\mathbf{\right)}$.