Glutaric acid, HOOCCH2CH2CH2COOH, contains?

Question

a. 14 σ and 2 π bonds	
	 b. 18 σ bonds	
	 c. 16 σ and 2 π bonds  	
	 d. 14 σ and 4 π bonds

the answer is c. can someone please tell me why?

? · Accepted Answer

This is a fun question! Okay, so think of it like this. 

Every SP3 bond has a sigma bond. Every SP2 bond has a sigma bond and a pi bond. Every SP bond has one sigma bond and two pi bonds.

I don't know how much you know about hybridization, but one thing that I do when I work out these kind of problems is draw out the entire compound, including the hydrogen bonds. If a carbon has only a single bond and no charges, its SP3. Two of the carbons on your molecule have double bonds, those carbons are SP2 and so the pi bonds are on those ketones. The hydroxyl groups are also SP3 and so the O-H is sigma.

http://www.bmrb.wisc.edu/metabolomics/standards/Glutaric_acid/lit/743.png 

If you count all of the single bonds in that molecule, you'll find that there are sixteen of them. If you count the double bonds, there are two of them.

Hope that helps!

Glutaric acid, HOOCCH2CH2CH2COOH, contains?

1 Answer