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

Options

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

Answer

B

Explanation

`NO: (sigma1s)^(2),(sigma^(**)1s)^(2),(sigma^(**)2s)^(2),(sigma2P_(z))^(2)`,
`(pi2P_(x))^(2)=(pi2P_(y))^(2),(pi^(**)2P_(x))^(1)=(pi^(**)2P_(y))^(0)`
`BO=(10-5)/(2)=2.5`
`CN^(-): (sigma1s)^(2),(sigma^(**)1s)^(2),(sigma2s)^(2),(sigma^(**)2s)^(2),(pi2P_(x))^(2)`
`=(pi2P_(y))^(2),(sigma2P_(z))^(2)`
`BO=(10-4)/(2)=3`
CN :` (sigma1s)^(2),(sigma^(**)1s)^(2),(sigma2s)^(2),(sigma^(**)2s)^(2),(pi2P_(x))^(2)`
`=(pi2P_(y))^(2),(sigma2P_(z))^(1)`
`BO=(9-4)/(2)=2.5`
`CN^(+): (sigma1s)^(2),(sigma^(**)1s)^(2),(sigma2s)^(2),(sigma^(**)2s)^(2),(pi2P_(x))^(2)`
`=(pi2P_(y))^(2)`
`BO=(8-4)/(2)=2`
Hence , option (2) should be the right answer.