Question

The decreasing order of bond angles in $BF_{3} , NH_{3} , PF_{3}$ and $I_{3}{^{-}}$ is

• A. $I_3{^{-}} > NH_3 > PF_3 > BF_3$
• B. $I_3{^{-}} > BF_3 > NH_3 > PF_3$
• C. $BF_3 > I_3{^{-}} > PF_3 > NH_3$
• D. $BF_3 > NH_3 > PF_3 > I_3{^{-}}$

Answer 1

Answer: (B)

$I_3{^{-}} > BF_3 > NH_3 > PF_3$

Answer 2

The shape of the given molecules is as follows:

$BF_3$ : Planar triangle with bond angles of $120^{\circ}$.

$NH _{3}$ : Trigonal pyramidal with bond angles of $107^{\circ} .$

$I _{3}^{-}$ : Linear with bond angles $180^{\circ}$.

$PF _{3}$ : Trigonal pyramidal with bond angles of $97.8^{\circ} .$