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 / \[2 \mathrm{NaHCO}_{3} \rightarrow \mathrm{Na}_{2} \mathrm{CO}_{3}+\mathrm{H}_{2} \mathrm{O}+\mathrm{CO}_{2}(\mathrm{~g}) \]