Which of the following are arranged in an increasing order of their bond strengths?

Options

A. `O_(2)^(-) lt O_(2) lt O_(2)^(+) lt O_(2)^(2-)`
B. `O_(2)^(2-) lt O_(2)^(-) lt O_(2) lt O_(2)^(+)`
C. `O_(2)^(-) lt O_(2)^(2-) lt O_(2) lt O_(2)^(+)`
D. `O_(2)^(+) lt O_(2) lt O_(2)^(-) lt O_(2)^(2-)`

Answer

B

Explanation

`O_(2)^(+)(15)=K K sigma 2s^(2), sigma*** 2s^(2), sigma 2p_(x)^(2), {pi 2p_(y)^(2)= pi2p_(z)^(2), { pi *** 2p_(y)^(1)=pi2p_(z)^(0)`
Bond order `=(1)/(2) (8-3) = (5)/(2)=2.5`
`O_(2)(16)= K K sigma 2s^(2), sigma***2s^(2) , sigma 2p_(x)^(2), {pi 2p_(y)^(2) = pi 2p_(z)^(2), { pi *** 2p_(y)^(1)=pi*** 2p_(z)^(1)`
Bond order `=(1)/(2)(8-4)=2 " " O_(2)^(-)(17)=K K sigma 2s^(2), sigma***2s^(2), sigma 2p_(x)^(2), {pi 2p_(y)^(2)= pi 2p_(z)^(2), {pi ***2p_(y)^(2)= pi***2p_(z)^(1)`
Bond order `=(1)/(2)(8-5)=1.5 " " O_(2)^(2-)(18)=K K sigma2s^(2)sigma***2s^(2) sigma2p_(x)^(2), {pi 2p_(y)^(2)=pi 2p_(z)^(2), {pi ***2p_(y)^(2)=pi***2p_(z)^(2)`
Bond order `=(1)/(2) (8-6)=1`
NOTE: As we know that as the bond order decreases, stability also decreases and hence the bond strength also decreases. Hence the correct order of their increasing bond strength is `O_(2)^(2-) lt O_(2)^(-) lt O_(2)lt O_(2)^(+)`
11 cases