Question

Names of some compounds are given. Which one is not correct in IUPAC system?

• A. $C{H}_3-\underset{OH}{\underset{|}{C}H}-\underset{C{H}_3}{\underset{|}{C}H}-C{H}_3$ 3-Methyl-2-butanol
• B. $\underset{4-methyl-2-pentyne}{{CH}_3-{CH}_2\equiv C-CH{\left({CH}_3\right)}_2}$
• C. $C{H}_3-C{H}_2-\underset{C{H}_2}{\underset{||}{C}-}\underset{C{H}_3}{\underset{|}{C}H}-C{H}_3$ 2-Ethyl-3-methyl-but-1-ene
• D. $C{H}_3-C{H}_2-C{H}_2-\underset{C{H}_{2}C{H}_3}{\underset{|}{C}H-}\stackrel{C{H}_3}{\stackrel{|}{C}H}-C{H}_{2}C{H}_3$ 3-Methyl-4-ethyl heptane

Answer 1

The correct option is D $C{H}_3-C{H}_2-C{H}_2-\underset{C{H}_{2}C{H}_3}{\underset{|}{C}H-}\stackrel{C{H}_3}{\stackrel{|}{C}H}-C{H}_{2}C{H}_3$

3-Methyl-4-ethyl heptane

$C{H}_3-\stackrel{6}{C}{H}_2-\stackrel{5}{C}{H}_2-\underset{C{H}_{2}C{H}_3}{\underset{|}{\stackrel{4}{C}}H-}\stackrel{C{H}_3}{\stackrel{3|}{C}H}-\stackrel{2}{C}{H}_2-\stackrel{1}{C}{H}_3$

Correct IUPAC name is $4-Ethyl-3-methyl$ $heptane$ because substituents are written in alphabetical order.

Hence, the correct option is $D$