Question

When using 3 grams of benzoin to oxidize to benzil, calculate the theoretical yield.

Procedure: 2 boiling stones are added to a 400-mL beaker half-full of water, then placed on a hot plate to boil. 3 grams of benzoin and 7 mL of concentrated nitric acid are then added to a 125 mL Erlenmeyer flask and placed in the boiling water bath and left to boil until the evolution of nitrogen dioxide has ceased. Then, 50 mL of ice-cold water is added to the reaction mixture.

After stoppering the flask and shaking to break-up large clumps of benzil, the product is collected by vacuum filtration and washed with ice-cold water to remove excess acid. The crude benzil is placed in a 50-mL flask with 10 mL of ethanol and then heated until dissolved. After cooling the mixture slowly in a cork stand and inverted beaker set up until long crystal needles form. In the event that crystals do not form, cold water is added dropwise to start the formation process. Once the crystals have formed, 50 mL of ice-cold water is added to the flask before the crystals are collected by suction filtration.

Answer 1