The number of `sigma and pi`- bonds in alkyl isocyanide are

Options

A. `9 sigma, 3pi`
B. `9 sigma, 9 pi`
C. `3 sigma, 4pi`
D. `5 sigma, 7pi`

Answer

A

Explanation

Isocyanides have the structure
`R-Noverset(rarr)=C:`
Allyl group is `CH_(2)=CH-CH_(2)-`
Thus, allyl isocyanide is
`H-underset(H)underset(|)C=underset(H)underset(|)C-underset(H)underset(|)overset(H)overset(|)C-Noverset(rarr)=C`
Every single bond is `sigma` bond, double bond contains one `sigma` and one `pi` bond, and triple bond contains one `sigma` and two `pi` bonds. Thus, the total number of `sigma` bonds is `9` and the total number of `pi` bonds is `3`.