Question

in the synthesis of pentaamminechlorocobalt(III) chloride through the reaction 2CoCl2·6H2O(s) + 2NH4Cl(s) + 8NH3(aq) + H2O2(aq) → 2[Co(NH3)5Cl]Cl2(s) + 14H2O(l)

What side reactions/impurities are occurring and how does suction filtration with water and then organic solvents help purify the precipitate?

Answer 1

In this reaction, the precipitate of pentaamminechlorocobalt(III) chloride will form. If the precipitate will not filtered then in the aqueous solution it will reform the aquopentaammine complex.

After completion of reaction, precipitate formed will filtered through Buchner suction filtration setup and washed with water and then organic solvents which helps to get purified precipitate. Now the question is how?

Water helps to remove the inorganic impurities from the precipitate like unused or unreacted NH4Cl.

Organic solvent helps to remove the organic impurities like aquopentaammine complex etc. After washing with water, organic solvent like Ethanol you can use to wash the precipitate this will help to get the dried precipitate because as compared to water, ethanol will evaporate easily.