Answer:
b. Extraction with a solution of sodium hydrogen carbonate, separating the layers, followed by drying and evaporating the organic layer.
Step-by-step explanation:
The ether solution contains your product, benzaldehyde, and some starting material, benzoic acid, the purification steps are:
- Extract with a solution of NaHCO₃. The ether layer contains benzaldehyde, and the aqueous layer contains sodium benzoate.
- Separate the layers. Keep the ether layer.
- Dry the ether solution.
- Distill the ether (boiling point 35 °C) and purify the benzaldehyde (178 °C) by steam distillation.
a. is wrong. Extraction with HCl will not remove much of the benzoic acid.
c. is wrong. If you evaporate the organic layer, you will have a mixture of benzaldehyde and benzoic acid.
d. is wrong. If you work with the aqueous layer, you will end up with benzoic acid,