Question

The IUPAC name of the compound $C{H}_3-CH(C{H}_3)-CO-C{H}_3$ is

• A. 3 - methyl - 2 - butanone
• B. 2 - methyl - 3 - butanone
• C. isopropyl methyl ketone
• D. 2 ethyl - 2 methyl pentane

Answer 1

Answer: (A)

(i) For the structure,



Functional group is ketone, hence its secondary suffix is ‘one’. Now, the longest carbon chain containing the functional group has $4$ carbon atom.

$\therefore$ The word root is ‘but’.

(ii) Further, since the longest chain is saturated, therefore its primary suffix is ‘ane’.

(iii) Number the carbon atoms right to left, it given lowest vacant $2$ to functional group and vacant $3$ to substituent methyl group.

$\therefore$ The $IUPAC$ name is $3$-methyl-$2$-butanone.