Question

Give a brief account of Baking Powder.

Answer 1

Baking Powder : It is a mixture of sodium bicarbonate and small amounts of corn starch and hydrogen tartrate. The chemical name of baking powder is sodium hydrogen carbonate.

Preparation : Carbon dioxide is passed through a saturated solution of sodium carbonate. Sodium bicarbonate, being sparingly soluble in water gets precipitated which is washed and dried in air. Requisite amounts of corn starch and hydrogen tartrate are then mixed.

$${Na}_2 {CO}_3+{CO}_2+{H}_2 {O} \longrightarrow 2 {NaHCO}_3({s})$$

It can also be prepared using sodium chloride as raw material.

$${NaCl}+{H}_2 {O}+{CO}_2+{NH}_3 \longrightarrow \begin{array}{cc}{NH}_4 {Cl} & +{NaHCO}_3 \text {  }\end{array}$$

Properties —

1. It is alkaline in nature.
2. At $100^{\circ} {C}$, It decomposes with evolution of ${CO}_2$ gas.

$$2 {NaHCO}_3 \longrightarrow {Na}_2 {CO}_3+{CO}_2+{H}_2 {O}$$

Uses : It is used —

• As a cooking agent.
• In medicines for neutralizing acidity in stomach.
• In soft drinks.
• In fire extinguishers.