Question

Which of these chemicals contains a carbon–carbon double bond?

1.C2H6
2.C2H4
3. C2H2

Answer 1

thoughts on this one?

try drawing the structures, each with a C-C chain, and distributing the hydrogen atoms on the carbons, such that each C has 4 electron pairs and each H has 1 electron pair

for example, the first choice would look like:


this only has a C-C single bond, so it wouldn't work

repeat this logic with the other choices