Question

Which of the following is the incorrect IUPAC nomenclature of given compounds?

• A. $C{H}_3-C{H}_2-C\equiv C-C{H}_3$
  Pent-2-yne
• B. $C{H}_3-\underset{C{H}_2}{\underset{||}{C}}-C{H}_2-C{H}_3$
  2-Methylenebutane
• C. $C{H}_3-C{H}_2-\underset{OH}{\underset{|}{C}H}-C{H}_3$
  Butan-2-ol
• D. $C{H}_3-\underset{Cl}{\underset{|}{C}}H-C{H}_2-C{H}_3$
  2-Chlorobutane

Answer 1

The correct option is B $C{H}_3-\underset{C{H}_2}{\underset{||}{C}}-C{H}_2-C{H}_3$

2-Methylenebutane
For assigning nomenclature of compound:
i). Select the longest carbon chain bearing functional group.
ii) Number the carbon chain so as the functional group gets loswest locant.

In (b), alkene is the functional group so it will constitute the principal carbon chain.