Question

Arrange the following hydrides in the increasing order of their reducing power:

• A. III < II < I < IV
• B. III < II < IV < I
• C. I < IV < II < III
• D. I < IV < III < II

Hint:

Reducing power of group 15 hydrides increases down the group due to weaker E-H bond strength.

Answer 1

The Correct Option is C

Step 1: Trend in group 15 hydrides.
Reducing capability strengthens descending the group: NH₃<PH₃<AsH₃<SbH₃.

Step 2: Ordering the given compounds.
The sequence of increasing reducing power is NH₃<PH₃<AsH₃<SbH₃.

Step 3: Final statement.
Thus, the correct ascending order is NH₃<PH₃<AsH₃<SbH₃.