sodium hydride Yield given. Multistep reaction;

1: 1.) sodium hydroxide / 1.) CH2Cl2, water, 2.) CH2Cl2, water, 0 deg C, 20 h 2: 1.) sodium hydride / 1.) chlorobenzene, mineral oil, 0 deg C, 1 h, 2.) chlorobenzene, mineral oil, room temperature, overnight View Scheme