# Hybridization of carbon atoms present in the smallest ester?

I found this question in the Resonance DLPD Organic Chemistry book on Page 55:

What is the hybridization of carbon atoms present in the smallest ester?

The smallest ester as far as I know is methyl formate ($$\ce{HCOOCH3}$$):

The first carbon atom (on left) has 3 σ bonds and the one on the right has 4 σ bonds. Hence, the hybridization is $$\mathrm{sp}^2$$ and $$\mathrm{sp}^3$$, respectively.

However, according to the answer given in the book, all carbon atoms in the smallest ester are $$\mathrm{sp}^2$$ hybridized.

What did I do wrong? Is there a smaller ester? Or the hybridization of the one I have above not correctly determined?

• Consider the hybrid obtained after resonance: This is only a canonical structure – YUSUF HASAN Feb 9 at 13:28
• @YUSUFHASAN sorry I don't know about resonance as I am only a high school student and have only recently started studying organic chemistry. – user69284 Feb 9 at 13:31
• Ok...See this could be either one of two cases: the book wanted you to consider only this structure,and so there is a misprint, as then the answer would be one sp2 and one sp3 carbon. Or, they wanted you to consider resonance, and understand the fact that the hybridization will be somewhere between sp2 and sp3(atleast I would have done that), but the answer doesn't show that.So,most probably,it is a misprint.Although, resonance should be taken into consideration as the actual existence is of the hybrid Check it out here – YUSUF HASAN Feb 9 at 13:37

You are right. Methyl formate has one $$\mathrm{sp}^2$$ and one $$\mathrm{sp}^3$$ hybridized orbital.