Question

Which of the following is the correct IUPAC name?

• A. 3 – Ethyl , – 4, 4 – dimethylheptane
• B. 4,4 – Dimethyl – 3 – ethylheptane
• C. 5 – Ethyl, – 4, 4 – dimethylheptane
• D. 4,4 – bis (methyl) – 3 – ethylheptane

Answer 1

Answer: (A)

3 – Ethyl , – 4, 4 – dimethylheptane

Answer 2

: While writing the name of the substituents in alphabetical order, the prefixes such as di, tri, tetra, penta, hexa etc, are not considered. As ‘e’ of ethyl comes before, ‘m’ of dimethyl thus, lower locant 3 is assigned to ethyl group and is written first.