Question

Arrange the following labelled hydrogens in decreasing order of acidity :

• A. $b > c > d > a$
• B. $c > b > a > d$
• C. $b > a > c > d$
• D. $c > b > d > a$

Answer 1

Answer: (A)

Acidic strength order :
$R -\overset{\underset{||}{O}}{C}- OH > R - OH > R - C \equiv CH$
Reason : $R - \overset{\underset{||}{O}}{C} - O^{\ominus}$ stable by equivalent resonance.
Stable :

So answer is $ b > c > d > a.$