1. Tardigrade
  2. Question
  3. Chemistry
  4. pKa increases in benzoic acid when substituent x is bonded at para-position, then x is

Q. increases in benzoic acid when substituent "x" is bonded at para-position, then "x" is

 3815  233 AIIMSAIIMS 2012Aldehydes Ketones and Carboxylic Acids Report Error

Solution:

Larger the value of pKa, smaller will be its acidity. Out of the four groups, -COOH, -NO2 and -CN are e- withdrawing which makes benzoic acid more acidic whereas -OCH3 is e- donating which reduces the acidity (makes H+ less easily available). pKa value increases if -OCH3 is present at para-position of benzoic acid.