How is the completeness of separation of benzoic acid and crystals from NaCl known with the addition of Silver Nitrate?what are the methods of...

AgNO3 + NaCl ----> NaNO3 + AgCl

After the reaction between NaCl and Silver Nitrate, the results are a precipitate of AgCl and aqueous NaNO3.

Silver Nitrate does not react with Benzoic acid.

Sodium benzoate reacts with Silver Nitrate but it will be less reactive in comparison to NaCl and will not precipitate.

 Good crystallizing solvent characteristics:

• The solid should be very soluble in the recrystallization solvent at high temperatures.

• The solid should be insoluble in the recrystallization solvent at room temperature or lower temperatures (i.e., an ice bath, 0°C).

•  Crystals should be obtained from the solvent as it cools.
• The solvent should have a relatively low boiling point so it can easily be removed via evaporation