Chemistry - GOC Question with Solution | TestHub

Chlorine's $-\mathrm{I}$ effect stabilizes chloroacetate and lowers the acid's ${\mathrm{pK}}_{\mathrm{a}}$. The ethyl group donates slightly more than methyl and makes propionic acid slightly weaker than acetic acid. Thus ${\mathrm{pK}}_{\mathrm{a}}({\mathrm{ClCH}}_2\mathrm{COOH})$ < ${\mathrm{pK}}_{\mathrm{a}}({\mathrm{CH}}_3\mathrm{COOH})$ < ${\mathrm{pK}}_{\mathrm{a}}({\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{COOH})$.