State one relevant observation - Barium chloride solution is slowly added to sodium sulphate solution.

Give a chemical test to distinguish between following pairs of chemicals :

(i) Lead nitrate solution and zinc nitrate solution.

(ii) Sodium chloride solution and sodium nitrate solution

Distinguish between the following pairs of compounds using the reagent given in the bracket.

(i) Manganese dioxide and copper [II] oxide [using conc. HCl]

(ii) Ferrous sulphate solution and ferric sulphate solution [using sodium hydroxide solution]

State one relevant observation for the following reaction : Zinc carbonate is heated strongly.