Question

The compound molecular in nature in gas phase but ionic in solid state is :

• A. $PC{l}_5$
• B. $CC{l}_4$
• C. $PC{l}_3$
• D. $POC{l}_3$
• E. None of the above

Answer 1

Answer: (A)

$PC{l}_5$

In gaseous and molten state $PC{l}_5$ is neutral molecule with trigonal bipyramidal symmetry.
In solid state $PC{l}_5$ is ionic which forms $PC{l}_4^{+}$, $PC{l}_6^{-}$. The cation and anion $PC{l}_4^{+}$, $PC{l}_6^{-}$ are tetrahedral and octahedral respectively.

Hence option A is correct.