Question

Which of the following oxoacids of phosphorus has two P-H bonds?

• A. Hypophosphoric acid
• B. Orthophosphoric acid
• C. Pyrophosphoric acid
• D. Hypophosphorous acid

Hint:

- Hypophosphorous acid (\(H_3PO_2\)) is a monobasic acid due to a single P-OH bond.
- It acts as a strong reducing agent in chemical reactions.
- Other phosphorus acids like \(H_3PO_4\), \(H_4P_2O_6\), and \(H_4P_2O_7\) do not have P-H bonds.

Answer 1

The Correct Option is D

Step 1: Understanding Oxoacids of Phosphorus 
- Phosphorus forms several oxoacids, each with a different number of P-H bonds. 
- The presence of P-H bonds determines their reducing properties. 

Step 2: Identifying the Acid with Two P-H Bonds 
- Hypophosphorous acid (\(H_3PO_2\)) has two P-H bonds. 
- Its structure consists of one P=O bond, one P-OH bond, and two P-H bonds. 

Step 3: Eliminating Other Options 
- Hypophosphoric acid (\(H_4P_2O_6\)) does not contain any P-H bonds. 
- Orthophosphoric acid (\(H_3PO_4\)) has only P-OH bonds. 
- Pyrophosphoric acid (\(H_4P_2O_7\)) also lacks P-H bonds. 

Step 4: Conclusion 
- Since Hypophosphorous acid (\(H_3PO_2\)) has two P-H bonds, the correct answer is Option (4).