Manipal Entrance Test 2015 Chemistry Paper

Nucleophile always attacks on electron deficient site. Presence of electron withdrawing group such as NO2 , CHO etc., decreases the electron density on benzene nucleous, hence such group activates the ring towards nucleophilic attack. While presence of electron releasing groups such as R or OR increase the electron density, thus deactivate the nucleus toward nucleophilie attack. NO2 group activate the ring more than Cl toward nucleophilic attack hence react readily with nucleophile.