Question

How will you distinguish between dilute hydrochloric acid and dilute sulphuric acid using lead nitrate solution?

Answer 1

Part 1: Dilute hydrochloric acid with and lead nitrate:-

1. When we react dilute hydrochloric acid with lead nitrate, it gives lead chloride and and nitric acid as its product.
2. This lead chloride is a white ppt and is soluble in hot water.
3. Balanced chemical reaction:- $\underset{(\mathrm{Lead}\mathrm{nitrate})}{\mathrm{Pb}{\left({\mathrm{NO}}_3\right)}_2\left(\mathrm{aq}\right)}+\underset{(\mathrm{Hydrochloric}\mathrm{acid})}{2\mathrm{HCl}\left(\mathrm{aq}\right)}\to \underset{(\mathrm{Lead}\mathrm{chloride})}{{\mathrm{PbCl}}_2\left(\downarrow \right)\left(\mathrm{white}\right)}+\underset{(\mathrm{Nitric}\mathrm{acid})}{2{\mathrm{HNO}}_3\left(\mathrm{aq}\right)}$

Part 2: Dilute sulphuric acid with and lead nitrate:-

1. When we react dilute sulphuric acid with lead nitrate, it gives lead sulfate and and nitric acid as its product.
2. This lead sulfate is a white ppt and it does not dissolve in hot water.
3. Balanced chemical reaction:- $\underset{(\mathrm{Lead}\mathrm{nitrate})}{\mathrm{Pb}{\left({\mathrm{NO}}_3\right)}_2\left(\mathrm{aq}\right)}+\underset{(\mathrm{Dil}.\mathrm{sulphuric}\mathrm{acid})}{{\mathrm{H}}_2{\mathrm{SO}}_4\left(\mathrm{aq}\right)}\to \underset{(\mathrm{Lead}\mathrm{sulphate})}{{\mathrm{PbSO}}_4\left(\downarrow \right)\left(\mathrm{white}\right)}+\underset{(\mathrm{Nitric}\mathrm{acid})}{2{\mathrm{HNO}}_3\left(\mathrm{aq}\right)}$

Final answer:- When dilute hydrochloric acid is treated with lead nitrate, lead chloride formed is soluble in hot water and when dilute sulphuric acid is treated with lead nitrate lead sulfate formed does not dissolve in hot water.