Question

In case of nitrogen, $NCl_{3}$ is possible but not $NCl_{5}$ while in case of phosphorous, $PCl_{3}$ as well as $PCl_{5}$ are possible. It is due to

• A. Availability of vacant d orbitals in $\text{P}$ but not in $\text{N}$
• B. Lower electronegativity of $\text{P}$ than $\text{N}$
• C. Lower tendency of H-bond formation in $\text{P}$ than $\text{N}$
• D. Occurrence of $\text{P}$ in solid while $\text{N}$ in gaseous state at room temperature.

Answer 1

Answer: (A)

${ }_7 \mathrm{~N}=1 \mathrm{~s}^2 2 \mathrm{~s}^2 2 \mathrm{p}^3 ;{ }_{15} \mathrm{P}=1 \mathrm{~s}^2 2 \mathrm{~s}^2 2 \mathrm{p}^6 3 \mathrm{~s}^2 3 \mathrm{p}^3$

In phosphorous the 3d-orbitals are available. Hence phosphorus can form pentahalides also but nitrogen cannot form pentahalide due to absence of d-orbitals.