Question

Observe the following reactions (unbalanced): 

\( P_2O_3 + H_2O \rightarrow X \)

\( P_4O_{10} + H_2O \rightarrow Y \)

The number of \( P=O \) bonds present in \( X, Y \) are respectively:

• A. \( 1, 3 \)
• B. \( 1, 2 \)
• C. \( 2, 1 \)
• D. \( 1, 1 \)

Hint:

Phosphorous acid (\( H_3PO_3 \)) and phosphoric acid (\( H_3PO_4 \)) both contain one \( P=O \) bond per molecule. Understanding the structure of oxyacids of phosphorus helps determine bond count.

Answer 1

The Correct Option is D

Step 1: Understanding the Hydrolysis of Phosphorus Oxides 
- \( P_2O_3 \) (Phosphorus(III) oxide) reacts with water to form phosphorous acid (\( H_3PO_3 \)): \[ P_2O_3 + 3H_2O \rightarrow 2H_3PO_3 \] - In \( H_3PO_3 \), there is one \( P=O \) bond. - \( P_4O_{10} \) (Phosphorus(V) oxide) reacts with water to form phosphoric acid (\( H_3PO_4 \)): \[ P_4O_{10} + 6H_2O \rightarrow 4H_3PO_4 \] - In \( H_3PO_4 \), there is also one \( P=O \) bond per molecule. 

Step 2: Evaluating the Given Options 
- Option (1): Incorrect, as \( X = H_3PO_3 \) has 1 \( P=O \) bond, and \( Y = H_3PO_4 \) also has 1 \( P=O \) bond.
- Option (2): Incorrect, as \( Y \) does not have 2 \( P=O \) bonds.
- Option (3): Incorrect, as \( X \) does not have 2 \( P=O \) bonds.
- Option (4): Correct, as both \( X \) and \( Y \) have 1 \( P=O \) bond each.
Thus, the correct answer is 

Option (4).