Answer:

CH3-CC-CH=CH2 is pent-1-en-3-yne.

There is an easy way to tell the hybridization of carbon.

sp carbon has coordination number 2, i.e. it has two nearest neighbors.

sp2 carbon has coordination number 3.

sp3 carbon has coordination number 4.

(Note: the carbon is tetravalent in each case: the difference comes from forming double and triple bonds to the same neighbor.)

So C1 of pent-1-en-3-yne is sp2 hybridized.

C2 is sp2 hybridized.

C3 is sp hybridized.

C4 is sp hybridized.

C5 is sp3 hybridized.

And that makes 2 sp hybridized, 2 sp2 hybridized, and 1 sp3 hybridized carbon.

Now, to convince yourself that you understand this, answer the question for pent-1-en-4-yne, HCC-CH2-CH=CH2.

Explanation: