Question (a) State your observation in each of the following cases :
(1) When dilute hydrochloric acid is added to sodium carbonate crystals.
(ii) When excess sodium hydroxide is added to calcium nitrate solution.
(ii) At the cathode when acidified aqueous copper sulphate solution is electrolyzed with copper electrodes.
(iv) When calcium hydroxide is heated with ammonium chloride crystals.
(v) When moist starch iodide paper is introduced into chlorine gas.​