Question

Which of the following is not hydrolysed?

• A. $AsCl_{3}$
• B. $PF_{3}$
• C. $SbCl_{3}$
• D. $NF_{3}$

Answer 1

Answer: (D)

$NF_{3}$

Answer 2

During hydrolysis water forms coordinate bonds with vacant orbitals of central atom. It means central atom must have vacant orbitals. (i) $P F_{3}$ has vacant 3 d orbitals of $P,\, AsH _{3}$ has vacant $4 d$ orbitals of $As,\, SbH _{3}$ has vacant $Sd$ orbitals of $Sb$. So all these compounds are hydrolysed. (ii) In $N F_{3}$, $N$ does not have vacant $d$ orbitals because it is member of second period. So $N F_{3}$ cannot be hydrolysed.