Final answer:
To remove excess base after synthesizing a soluble salt from an acid and an insoluble base, the solution should be filtered. Filtration separates the unreacted insoluble base from the solution, leaving the dissolved salt in the filtrate.
Step-by-step explanation:
To remove excess base after making a soluble salt from an acid and an insoluble base, the solution must be filtered. This is because after the reaction has completed, the excess insoluble base will not have reacted and can be separated from the soluble salt solution by filtration. Filtration will leave behind the insoluble substances, such as the excess base, on the filter paper, and allow the soluble salt to pass through as a filtrate.
In the process of synthesizing compounds, recrystallization is often used to purify the target product. The purification process involves dissolving the compound in a hot solvent and, upon cooling, the desired compound precipitates, leaving impurities still dissolved in the solvent. This principle does not directly apply to removing excess base through filtration.
Other processes like evaporation and distillation are used for concentrating solutions or separating components based on volatility, which are not applicable to the direct removal of excess solid base from a solution. The process of filtration is well illustrated in materials such as Figure 3.6.4, which shows the separation of solids from a hot solution.