Question

Sodium chloride was used as an important symbol in our freedom struggle. Mahatma Gandhi and his followers did Dandi march in order to stop the British government from increasing the price of common salt used daily by Indian people.. How is sodium chloride prepared and purified?

Answer 1

Part I - Preparation

• Sodium chloride is obtained by mining the deposits, and brine solution is obtained by passing water into the deposits.
• The solution is pumped out after dissolving salt.
• Salt can be obtained by the evaporation of seawater.
• Salt can be prepared by the reaction of sodium and chloride.

$$\begin{gathered} 2\mathrm{Na}\left(\mathrm{s}\right)+{\mathrm{Cl}}_2\left(\mathrm{g}\right)\to 2\mathrm{NaCl}\left(\mathrm{s}\right) \\ \mathrm{sodium}\mathrm{chlorine}\mathrm{sodium}\mathrm{chloride} \end{gathered}$$

Part II - Purification

• Sodium chloride can be purified by passing hydrogen chloride gas through an impure solution of brine.
• This takes place by the common ion effect.
• Hydrogen chloride is a strong electrolyte that provides chloride ion that is furnished by the weak electrolyte.
• Therefore weak electrolyte ionization suppression takes place.