Consider the following species
`CN^(-),CN^(-),NO and `CN`.
Which one of these will hqave the highest bond order ?

Options

A. `NO`
B. `CN^(-)`
C. `CN^(+)`
D. `CN`

Answer

B

Explanation

`NO:KK(sigma2s)^(2)(2sigma^(**)2s)^(2)(pi2p_(x))^(2)=(pi2p_(y))^(2)(sigma2p_(z))^(2)(pi^(**)2p_(x))^(1)`
`"B.O."=(8-3)/(2)=2.5`
`CN^(-1):(sigma2s)^(2)(sigma^(**)2s)^(2)(pi2p_(x))^(2)=(pi2p_(y))^(2)(sigma2p_(z))^(2)`
`B.O.=(8-2)/(2)=3`
`CN:KK(sigma2s)^(2)(sigma^(**)2s)^(2)(pi2p_(x))^(2)=(pi2p_(y))^(2)(sigma2p_(z))^(1)`
`B.O.=(7-2)/(2)=2.5`
`CN^(+):KK(sigma2s)^(2)(sigma^(**)2s)^(2)(pi2p_(x))^(2)=(pi2p_(y))^(2)`
`B.O.=(6-2)/(2)=2`
Hence `CN^(-)` has highest bond order.