Question

The number(s) of -OH group(s) present in H₃PO₃ and H₃PO₄ is/are:

• A. 3 and 3 respectively
• B. 3 and 4 respectively
• C. 2 and 3 respectively
• D. 1 and 3 respectively

Hint:

The structure of oxyacids of phosphorus determines the number of -OH groups. Check for direct P-H bonds and P=O bonds.

Answer 1

The Correct Option is C

• H₃PO₃: Contains two -OH groups and one H atom directly bonded to P.
• H₃PO₄: Contains three -OH groups and one P=O bond.

Answer 2

The number(s) of -OH group(s) present in H3PO3 and H3PO4 is/are:

• Option 1: 3 and 3 respectively
• Option 2: 3 and 4 respectively
• Option 3: 2 and 3 respectively
• Option 4: 1 and 3 respectively

Correct Answer:

Option 3: 2 and 3 respectively

Explanation:

• H3PO3 (Phosphorous Acid): It has two -OH groups and one P-H bond.
• H3PO4 (Phosphoric Acid): It has three -OH groups and one P=O bond.