Question

Esters of chrysanthemic acid are naturally occurring insecticides. How many lines are present in the NMR spectrum of chrysanthemic acid?

Short answer

The ¹³C NMR spectrum consists of nine lines.

Step-by-step solution

13C  NMR spectroscopy

The ¹³C NMR spectroscopy is used to describe the carbon environment of a compound.

The signals in the ¹³C NMR spectrum give the number of equivalent and non-equivalent carbon atoms which is used to interpret the structure of an unknown compound.

Equivalent and non-equivalent carbon atoms

The carbon atoms that have the same chemical environment and that resonate at the same frequency are termed chemically equivalent.

The carbon atoms that have a different chemical environment and that resonate at different frequencies are termed non-equivalent carbon atoms.

Number of lines in the 13C NMR spectrum of chrysanthemic acid

Non-equivalent carbon atoms in chrysathemic acid

There are nine non-identical carbon atoms in chrysanthemic acid and hence its ¹³C NMR spectrum consists of nine signals/lines.