Question

Why would a reprecipitation be employed in a gravimetric analysis?

Short answer

The reprecipitation method in the gravimetric analysis is used for reducing the level of impurities.

Step-by-step solution

Precipitation:

Precipitation gravimetry is an analytical technique that uses a precipitation reaction to separate ions from a solution. The chemical that is added to cause the precipitation is called the precipitant or precipitating agent.

During first precipitation, impurities are present in high concentrations and also are unwanted species.

Reprecipitation:

After returning a precipitate to a dissolved state, the process of precipitating it again.

During reprecipitation, precipitate is purer due to reduced level of impurities in a solution.