Question

Which of the following statements are correct?
(i) All the three $N—O$ bond lengths in $HNO_{3}$ are equal.
(ii) All $P—Cl$ bond lengths in $PCl_{5}$ molecule in gaseous state are equal.
(iii) $P_{4}$ molecule in white phohsphorus have angular strain therefore white phosphorus is very reactive.
(iv) $PCl_{5}$ is ionic in solid state in which cation is tetrahedral and anion is octahedral.

• A. (i) and (iv)
• B. (iii) and (iv)
• C. (ii) and (iii)
• D. (ii) only

Answer 1

Answer: (B)

(iii) White phosphorus consists of discrete tetrahedral $P _4$ molecules. It is more reactive than the other solid phases because of angular strain in the molecule where the angles are only $60^{\circ}$.
(iv) In the solid state, $PCl _5$ exists as an ionic solid $\left[ PCl _4\right]^{+}$ $[ PCl_6]^{-}$in which the cation, $\left[ PCl _4\right]^{+}$is tetrahedral and the anion $\left[ PCl _6\right]^{-}$is octahedral.