Question

The correct order of increasing acid strength of the compounds:
(A) $C{H}_{3}C{O}_{2}H$
(B) $MeOC{H}_{2}C{O}_{2}H$
(C) $C{F}_{3}C{O}_{2}H,$
(D) $(C{H}_3{)}_{2}CCOOH$:

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

Answer 1

Answer: (C)

$d<a<b<c$

$a.C{H}_3-COOH$, $b.C{H}_{3}O-C{H}_2-COOH$ $c.C{F}_{3}COOH$ $d.(C{H}_3{)}_{2}CH-COOH$

In the given compounds the common group is $C-COOH$

Acidity $\propto \frac{1}{+I-group}\propto -I-group$
Here the $+I$ group is $-C{H}_3$
and $-I$ groups are $MeO-$ and $F-$

There are three $F$ in the compound $d$, hence it is the most acidic compound.
The correct order is $d<a<b<c$
Option C is correct.