Question

Give the number of $\sigma$ and $\pi$ bonds in (i)$C_2^{2-}$ (ii)$C_3^{4-}$ and (iii)$C{N}_2^{2-}.$

• A. (i) 2 $\sigma$, 1 $\pi$; (ii) 1 $\sigma$, 3 $\pi$; (iii) 2 $\sigma$, 2 $\pi$
• B. (i) 2 $\sigma$, 1 $\pi$; (ii) 3 $\sigma$, 1 $\pi$; (iii) 2 $\sigma$, 2 $\pi$
• C. (i) 1 $\sigma$, 2 $\pi$; (ii) 2 $\sigma$, 2 $\pi$; (iii) 2 $\sigma$, 2 $\pi$
• D. (i) 1 $\sigma$, 2 $\pi$; (ii) 3 $\sigma$, 1 $\pi$; (iii) 2 $\sigma$, 2 $\pi$

Answer 1

Answer: (C)

(i) 1 $\sigma$, 2 $\pi$; (ii) 2 $\sigma$, 2 $\pi$; (iii) 2 $\sigma$, 2 $\pi$

$(i{)}^{-}\text{C}\equiv C^{-}$ one $\sigma$, two $\pi$; (ii) ${}^{-}\text{C}\equiv C-C^{3-}$ two $\sigma$, two $\pi$; (iii) ${}^{-}\text{N}=C=N^{-}$ two $\sigma$, two $\pi$
Hence option C is correct.