Question

$\underset{\underset{Cl}{|}}{C{H}_2}-OH$ is more acidic than $\underset{\underset{N{O}_2}{|}}{C{H}_2}-C{H}_2-OH$

• A. True
• B. False

Answer 1

The correct option is A

True

Whenever there is a difference in the distance between two electronegative groups, the intensity of effect decreases when the distance from the source increases.

The acidity of effect alcohols depends on the stability of alkoxide ion (i.e., the conjugate base of alcohol) which is obtained by the dissociation of alcohols.

$R-O-H\rightleftharpoons R-\stackrel{\ominus }{O}+\stackrel{\oplus }{H}$

Acid strength of alcohol $\alpha$ stability of alkoxide ion

The stability of the alkoxide ion depends on the -I effect of the group attached. -I effect stabilises the alkoxide ion as a result of the reduction in charge density on the oxygen atom.

In our case, -I effect of $Cl$ is greater because of its proximity as we discussed.

$\underset{\underset{Cl}{|}}{C{H}_2}-OH$ $\underset{\underset{N{O}_2}{|}}{C{H}_2}-C{H}_2-OH$

I is more acidic than II even though the -I effect of $N{O}_2$ is higher.