Question:
The correct decreasing order of acidity of alkynes is
The correct decreasing order of acidity of alkynes is
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Terminal alkynes are acidic; internal alkynes are almost non-acidic.
Updated On: Apr 24, 2026
- \(CH \equiv CH>CH_3 - C \equiv CH>CH_3 - C \equiv C - CH_3\)
- \(CH_3 - C \equiv C - CH_3>CH \equiv CH>CH_3 - C \equiv CH\)
- \(CH_3 - C \equiv CH>CH \equiv CH>CH_3 - C \equiv C - CH_3\)
- \(CH \equiv CH>CH_3 - C \equiv C - CH_3>CH_3 - C \equiv CH\)
- \(CH_3 - C \equiv CH>CH_3 - C \equiv C - CH_3>CH \equiv CH\)
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The Correct Option is A
Solution and Explanation
Concept:
Acidity of alkynes depends on stability of conjugate base (acetylide ion).
Step 1: Understand acidity trend.
• Terminal alkynes (\(RC \equiv CH\)) are acidic
• More alkyl groups $\rightarrow$ electron donating $\rightarrow$ less acidic
Step 2: Compare compounds.
• \(CH \equiv CH\) $\rightarrow$ most acidic
• \(CH_3 - C \equiv CH\) $\rightarrow$ less acidic
• \(CH_3 - C \equiv C - CH_3\) $\rightarrow$ least acidic
Step 1: Understand acidity trend.
• Terminal alkynes (\(RC \equiv CH\)) are acidic
• More alkyl groups $\rightarrow$ electron donating $\rightarrow$ less acidic
Step 2: Compare compounds.
• \(CH \equiv CH\) $\rightarrow$ most acidic
• \(CH_3 - C \equiv CH\) $\rightarrow$ less acidic
• \(CH_3 - C \equiv C - CH_3\) $\rightarrow$ least acidic
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