Prelab for “Preparation and Carbonation of a Grignard Reagent: Synthesis of Benzoic
Acid”
Name:
Section:
1. Write a chemical reaction showing the product expected from the reaction between
phenylmagnesium bromide and dry ice. Then write another chemical reaction showing the
product from phenylmagnesium bromide and acetone. Comment on the similarity of these
two reactions.
2. Benzoic acid does not dissolve in cold water to any great extent. However, when the solid is
added to 5% cold aqueous NaOH solution, it completely dissolves. Explain this fact with the
help of chemical equations.
3. Look up the 1H chemical shift for the COOH proton. Explain why it is so deshielded.
4. Explain why the IR frequency for the OH in benzoic acid is lowered to about 3000 cm-1 from
3300 cm-1 observed for a normal alcohol.