Question

Match list I and list II.
List I List II
A. $N{F}_3$ 1. No hydrolysis
B. $P{F}_3$ 2. Hydrolysed by hydrogen bonding
C. $NC{l}_3$ 3. Hydrolysed by nucleophilic attack
D. $AsC{l}_3$ 4. Lewis base
5. Lewis acid

• A. A - 1,4; B - 1,4,5; C - 2,4; D - 3,4,5
• B. A - 1; B - 1,4; C - 2,5; D - 3
• C. A - 2,4; B - 1,5; C - 2; D - 4
• D. A - 4; B - 3; C - 1,2; D - 5

Answer 1

The correct option is A A - 1,4; B - 1,4,5; C - 2,4; D - 3,4,5

$N{F}_3$ is not hydrolysed because of the absence of $d-$orbital in $N$ or $F$. $P{F}_3$ is not hydrolysed because $P-F$ bond is stronger than $P-O$ bond. $NC{l}_3$ is hydrolysed due to hydrogen bonding between $N$ of $NC{l}_3$ and $H$ of $H_{2}O$. $AsC{l}_3$ is hydrolysed by nucleophilic attack by $H_{2}O$ on $As$ which has very low electronegativity. All the four have lone pairs on the central atom. So they act as Lewis bases.
$P{F}_3$ and $AsC{l}_3$ can act as Lewis acid by accommodating an additional pair of electrons on the central atoms in their vacant $d-$orbitals.