The following method is used to prepare a pure sample of ester GGG:
- Step 1: Mix 12 cm312\text{ cm}^312 cm3 of ethanol with 15 cm315\text{ cm}^315 cm3 of propanoic acid in a reaction flask. Add 555 drops of concentrated sulfuric acid and some anti-bumping granules. Assemble the reflux chemistry apparatus and heat the mixture.
- Step 2: Transfer the cooled mixture to a separating funnel. Add 20 cm320\text{ cm}^320 cm3 of aqueous sodium carbonate, stopper the funnel, and shake the mixture.
- Step 3: Run off the organic layer into a beaker, add anhydrous calcium chloride, and decant the liquid.
- Step 4: Purify the ester using distillation.
Answer the following questions based on this preparation method:
- Explain the purpose of adding anti-bumping granules in Step 1.
- State the purpose of adding aqueous sodium carbonate in Step 2.
- Suggest a precaution (with a reason) that should be taken while shaking the mixture in the separating funnel in Step 2.
- State the function of the anhydrous calcium chloride in Step 3.
- Suggest how the purity of ester GGG can be confirmed during the distillation in Step 4.