Match the procedural step to its purpose. a. Flat-bottomed flasks transfer heat in an uneven fashion, and may fracture if heated strongly.
b. Methanol, which is used as a reagent and solvent, is flammable.
c. The unreacted carboxylic acid was neutralized under mild conditions.
d. Water needs to be removed before the liquid ester product is collected.

1. Magnesium sulfate is added to the dichloromethane layer before the solvent is distilled off.
2. The reagents were added to a round bottom flask prior to the reaction being heated under reflux.
3. The solution of benzoic acid and methanol was heated on a steam bath.
4. The reaction mix was washed with sodium carbonate solution.