What else is produced during the replacement reaction of silver nitrate and potassium sulfate

Chemistry worksheet - i am not sure what they are asking for exactly?

Correct relationship between molecular formula and empirical formula

Some liquids can be distilled, but only at temperatures that are so high that it is impractical, or so high the compound decomposes. explain why distillation such compounds at significantly less than atmospheric pressure (some degree of vacuum) would solve this problem.