Question

Which of the following hydrocarbons has acidic hydrogen's?

• A. 1-butane
• B. 1-butyne
• C. 2-butene
• D. 2-butyne

Answer 1

Answer: (B)

H-atom attached with triple bonded carbon atoms are acidic in nature.
The structures of the given compounds are as
[a] $\underset{1-\text{butene}}{C{H}_2=CH-C{H}_{2}C{H}_3}$
[b] $\underset{1-\text{butyne}}{CH\equiv C-C{H}_{2}C{H}_3}$
[c] $\underset{2-\text{butene}}{C{H}_{3}CH=CHC{H}_3}$
[d] $\underset{2-\text{butyne}}{C{H}_{3}C\equiv CC{H}_3}$
Hence, acidic hydrogen is present only in $1$-butyne.