Chapter 33, Problem 1Q

Interpretation Introduction

Interpretation : We need to interpret the formation of benzene as the side product during the Grignard reaction while using phenyl magnesium bromide with the help of a balanced chemical equation.

Concept Introduction : Grignard reagent is a chemical compound with a general formula $\text{RMgX}$ . Here $\text{R}-$ indicates an alkyl or aryl group that is directly bonded with magnesium metal by an organometallic bond.

The Grignard reagent is widely used in the organic synthesis of various chemical compounds due to its high reactivity of it.

Answer to Problem 1Q

The hydrolysis of phenyl magnesium bromide forms benzene as the side product. The balanced chemical equation can be written as:

  

Explanation of Solution

In the Grignard reagent, the alkyl or aryl group acts as a strong nucleophile therefore it can react easily with carbonyl compounds to form alcohols. It can readily react with water that breaks the $-\text{MgX}$ part to form alkane (hydrocarbon) and basic bromide.

Thus, hydrolysis of phenyl magnesium bromide forms benzene as a side product. This can occur if the glassware is not completely dry. The balanced chemical equation can be written as:

  

Conclusion

Grignard reagent is unstable in water and readily decomposes to alkane and respective alcohol.