Question

Which one of the following pairs of species have
the same bond order ?
A. `CO, NO`
B. `O_(2), NO^(+)`
C. `CN^(-) , CO`
D. `N_(2), O_(2)^(-)`

Answer 1

Correct Answer - C
M.O. configuration of `CN^(-)` ion `(14e^(-))` is
`KK sigma (2s)^(2) sigma^(**)(2s)^(2) pi(2p_(x))^(2) pi (2p_(y))^(2) pi (2p_(z))^(2)`
B.O. ` = (8-2)/(2) = (6)/(2) = 3 `
M.O. cofiguration of CO `(14r^(-))` :
`KK sigma (2s)^(2) pi (2p_(y))^(2) pi (2p_(y))^(2) sigma (2p_(z))^(2) sigma^(**) (2s)^(2) `
B.O. ` = (8-2)/(2) = (6)/(2) = 3 `
Thus , `CN^(-)` and CO have same bond order .