Sodium Bicarbonate (Baking Soda) NaHCO3

Sodium Bicarbonate

It is obtained as the intermediate product in the solvay ammonia soda process. Normal carbonate can be changed to bicarbonate by passing carbon dioxide through its saturated solution.

Na₂CO₃ + CO₂ + H₂O 2NaHCO₃

Sparingly soluble

Properties

It is a white crystalline solid, sparingly soluble in water. The solution is alkaline in nature due to hydrolysis. The solution is weakly basic.

NaHCO₃ + H₂O NaOH + H₂CO₃

The solution gives yellow colour with methyl orange but no colour with phenolphthalein.

On heating, it loses carbon dioxide and water forming sodium carbonate.

2NaHCO₃ Na₂CO₃ + H₂O + CO₂

The metal salt which forms basic carbonate with sodium carbonate, gives normal carbonate with sodium bicarbonate.

ZnSO₄ + 2NaHCO₃ ZnCO₃ + Na₂SO₄ + H₂O + CO₂

Uses

(i) It is used as a medicine (sodabicarb) to neutralize the acidity in the stomach.

(ii) It is largely used for making baking powder. Baking powder is a mixture of potassium hydrogen tartrate and sodium bicarbonate.

(iii) It is used in making effervescent drinks.

(iv) It is used in fire extinguishers.

(v) It is used for production of carbon dioxide.