Write the preparation of Baking soda. How does it help in making cakes soft and spongy ?

Baking soda is prepared by passing carbon dioxide and ammonia gas through aqueous solution of sodium chloride. / \[\mathrm{NaCl}+\mathrm{H}_{2} \mathrm{O}+\mathrm{NH}_{3}+\mathrm{CO}_{2} \rightarrow \mathrm{NaHCO}_{3}+\mathrm{NH}_{4} \mathrm{Cl} \]

Baking soda on heating releases \(\displaystyle \mathrm{CO}_{2}\) gas which makes cakes soft and spongy / \[2 \mathrm{NaHCO}_{3} \rightarrow \mathrm{Na}_{2} \mathrm{CO}_{3}+\mathrm{H}_{2} \mathrm{O}+\mathrm{CO}_{2}(\mathrm{~g}) \]