Question

In case of nitrogen, \( \text{NCl}_3 \) is possible but not \( \text{NCl}_5 \), while in case of phosphorus, \( \text{PCl}_3 \) as well as \( \text{PCl}_5 \) is possible. It is due to:

• A. availability of vacant \( d \)-orbitals in P but not in N
• B. lower electronegativity of P than N
• C. lower tendency of H-bond formation in P than N
• D. occurrence of \( \text{P} \) in solid while \( \text{N} \) in gaseous state at room temperature

Hint:

Phosphorus can form higher oxidation states like \( +5 \) due to the availability of vacant \( d \)-orbitals, unlike nitrogen.

Answer 1

The Correct Option is A

Step 1: Phosphorus can expand its valency by utilizing vacant \( d \)-orbitals in its outer shell, enabling it to form \( \text{PCl}_5 \), while nitrogen cannot due to the absence of such \( d \)-orbitals.

Final Answer: \[ \boxed{\text{availability of vacant } d\text{-orbitals in P but not in N}} \]