Visualize the structural formula of each of the following hydrocarbons. which hydrocarbon has a double bond in its carbon skeleton?
(a) c3h8
(b) c2h6
(c) c2h4
(d) c2h2

C₂H₄

Explanation:

A hydrocarbon with a double bond is called an alkene. The general formula for an alkene is CₙH₂ₙ where as the n represents the number of carbons.

Taking your problem as an example:

C₂H₄ has 2 carbons, as indicated by the subscript beside the chemical symbol of Carbon.

if C = 2 then n = 2

CₙH₂ₙ = C₂H₂₍₂) = C₂H₄

as many times as you want

sorry, but you do not have posted the diagram.