Answer to Question #202664 in Organic Chemistry for Gaurav Dhiran

Question

Giving reasons arrange the following in increasing order of their vO-H frequency: ethanol, trichloroacetic acid, acetic acid and chloroacetic acid

Answer 1

The acid strength of acetic acid is lower than that of formic acid, as the methyl group is an electron releasing group and destabilizes the carboxylate anion.

Chlorine and fluorine are electron withdrawing groups. They stabilize the carboxylate anion.

Hence, trichloroacetic acid and trifluoro acetic acid are more acidic than formic acid.

Fluorine is more electron withdrawing than chlorine. Hence, trichloroacetic acid (A) is less acidic than trifluoroacetic acid (B).

Therefore, the correct order increasing acid

Acetic acid, formic acid,trichloroacetic acid, Trifluoro acetic acid.