Question

Benzophenone reacts with phenylmagnesium bromide in ether solution to make triphenylmethanol after acid workup. Which of the following experimental mistakes will decrease the effectiveness of a Grignard reaction? Select all answers that apply.

1. The magnesium ribbon is insoluble in ether.
2. The glassware was not dried before use.
3. The fume hood was too cold.
4. The magnesium ribbon was not wiped clean before use.

Answer 1

2. The glassware was not dried before use

4. The Magnesium ribbon was not wiped clean before use

Step-by-step explanation:

Necessary precautions are required to be taken in the laboratory when Benzophenone reacts with phenylmagnesiumbromide in ether solution to produce Triphenylmethanol. Such precautions include proper drying of any glasswares used as well as the use of tight sealing glasswares during this experiment to ensure that the Grignard reaction is free of any traces of water or moisture. Any presence of moisture during the reaction would result in a decrease in the yield of triphenylmethanol produced thereby resulting in the decrease of the effectiveness of the Grignard reaction.