1 Why is acetic acid an appropriate solvent in which to perf

1. Why is acetic acid an appropriate solvent in which to perform rate studies of electrophilic brominations?

2. Why is the first step of an electrophilic aromatic bromination reaction endothermic?

3. Calculate the final concentration of bromine in the test tube when 1.5 ml of 0.05 M bromine is added to 1.5 ml of substrate stock solution, so that the final volume is 3.0 ml of bromine and substrate combined.

Solution

ans 1.  If water is present, bromine will react with water, rather than with substrate . This is why glacial acetic acid is used. It\'s also easily removed in an aqueous workup.

ans 2. The loss of aromaticity required to form the sigma bond between bromine and the aromatic substrate explains the highly endothermic nature of the first step.

ans 3. M₁V₁=M₂V₂

where M₁=0.05M

V₁=1.5mL

  V₂ =3mL

putting the value in above equation

M₂=0.025 M