question: which species is/are sp2 hybridized?

[clarisse]

This is a question from a multiple choice exam but I am not sure if I got the answer right:

 

which species is/are sp2 hybridized?

I. C2H4

II. C2H6

III. C3H6

 

a. I only

b. I and II only

c. I and III only

d. II and III only

 

Well II I obviosly know it isn't because it must be sp3 hybridized. Oh I think I see now, because the other ones formm double bonds they must be sp2 hybridized? Am I right?

[Hephaestus]

Easiest way to check - if a carbon is bound to three other atoms it is sp2 hybridised. Only C2H4 obeys this

 

C3H6 has two sp2 carbons and one sp3 (sp3 is bound to 4 atoms).

[Darkblade48]

In general, carbon atoms that are singly bonded to other carbon atoms are sp3; double bonds indicate sp2, and triple bonds indicate sp.

[ecoli]

another hint... drawing them should make things clear.

[clarisse]

Thanks for the help everyone. I had the test today and I only one question had to do with hybridization.