Question

What is salt? What kind of salt is prepared by precipitation?

Answer 1

Salt

• Salts are substances created by reacting an acid with a base.
• The formation of salt from an acid and a base is known as neutralization.
• Examples of salts: Sodium chloride $\left(\mathrm{NaCl}\right)$, and Calcium chloride$\left({\mathrm{CaCl}}_2\right)$.

Chemical reaction

• The chemical reaction is as follows-

$$\begin{gathered} {\mathrm{H}}^{+}{\mathrm{Cl}}^{-}\left(\mathrm{aq}\right)+{\mathrm{Na}}^{+}{\mathrm{OH}}^{-}\left(\mathrm{aq}\right)\to {\mathrm{Na}}^{+}{\mathrm{Cl}}^{-}\left(\mathrm{aq}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right) \\ \mathrm{Acid}\mathrm{Base}\mathrm{Salt}\mathrm{Water} \end{gathered}$$

Salt Preparation by Precipitation Method

• Insoluble salts can be prepared by precipitation reactions.
• For example: When Barium chloride $\left({\mathrm{BaCl}}_2\right)$ reacts with sulfuric acid $\left({\mathrm{H}}_2{\mathrm{SO}}_4\right)$, it results in the formation of Barium sulfate $\left({\mathrm{BaSO}}_4\right)$ and Hydrochloric acid $\left(\mathrm{HCl}\right)$.
• In this case, Barium sulfate $\left({\mathrm{BaSO}}_4\right)$ is an insoluble salt.

Chemical reaction

• The chemical reaction is as follows:

${\mathrm{BaCl}}_2\left(\mathrm{aq}\right)+{\mathrm{H}}_2{\mathrm{SO}}_4\left(\mathrm{aq}\right)\to {\mathrm{BaSO}}_4\downarrow +2\mathrm{HCl}\left(\mathrm{aq}\right)$