Question

What structural feature is indicated by the suffix -ene in the name of a hydrocarbon?

Answer 1

A site of unsaturation, namely a vinyl group.

Explanation:

`"Ethylene"` or `"Ethene"`, is `H_2C=CH_2`; `"propylene"`, or `"propene"`, is `H_3C-CH=CH_2`. The `"ene"` suffix designates an olefinic bond.