Question

The compound used in the preparation of borax is:

• A. Sodium carbonate.
• B. Sodium chloride.
• C. Washing soda.
• D. Sodium tetraborate.

Hint:

Washing soda (Na₂CO₃·10H₂O) is a source of sodium carbonate, which is used to prepare borax in the reaction with boric acid.

Answer 1

The Correct Option is C

Step 1: Understanding the preparation of borax.
Borax is a chemical compound commonly used in various industrial and household applications. It is primarily prepared from washing soda (sodium carbonate decahydrate, \( \text{Na}_2\text{CO}_3 \cdot 10\text{H}_2\text{O} \)) and boric acid (\( \text{H}_3\text{BO}_3 \)). Step 2: Reaction.
The preparation involves the reaction of sodium carbonate with boric acid: \[ Na_2CO_3 + 2H_3BO_3 \rightarrow 2NaCl + CO_2 + H_2O \] Step 3: Conclusion.
Thus, washing soda is used in the preparation of borax.