Final answer:
The distillation flask should be securely placed on a heat source connected to a condenser and receiving flask to collect distilled water. The solution needs to be mixed well, and heating should cease when the liquid fully vaporizes before sealing for condensation.
Step-by-step explanation:
In setting up the distillation flask and three-way adapter assembly, make sure the distillation flask contains the salt water solution and is placed securely on a heat source, such as a Bunsen burner.
The flask should be connected to the condenser where cool water enters and warm water exits to efficiently condense the vapor into a liquid. Equally important is the position of the receiving flask, which will collect the pure distilled water. It's crucial to swirl the solution until it dissolves completely, and then fill the flask to the line marked on its neck. Once capped, invert the flask multiple times for thorough mixing. When heating the mixture, remove the flask from the heat source just as the last bit of liquid vaporizes to ensure the flask is only filled with gas at ambient pressure. Seal the flask to allow the gas to condense back into a liquid state for accurate weighing.