Question

Give a reason for each of the following laboratory practices:

I. KMnO4 solution is not acidified with HNO3 before titration
II.FeSO4 solution is usually prepared fresh when needed
III. Alkali are not stored in glass stoped reagent bottles

Answer 1

See explanation

Step-by-step explanation:

The acid commonly used to acidify KMnO4 is H2SO4. The reason why HNO3 is not used is because HNO3 is itself a strong oxidizing agent. HCl is not used because it can react with KMnO4.

FeSO4 solution is usually prepared fresh when needed because if the solution is prepared and left to stand for sometime, FeSO4 is oxidized to Fe2(SO4)3 by air. Fe III does not give the brown ring test.

Alkali are not stored in glass stopped reagent bottles because very strong alkali can cause the stopper to corrode and fuse to the neck of the bottle making it very difficult to open the reagent bottle.