State your observations in each of the following:
(a) Dilute hydrochloric acid is added to calcium hydrogen carbonate.
(b) At the cathode, acidified aqueous copper sulphate solution is electrolysed with copper electrodes.
(c) Moist starch iodide paper is introduced into chlorine gas.
(d) Calcium hydroxide is heated with ammonium chloride crystals.
(a) When dilute hydrochloric acid is added to calcium hydrogen carbonate, carbon dioxide gas is released with effervescence, and a solution of calcium chloride is formed along with water.
(b) Copper, a brownish pink metal is deposited at the cathode when acidified aqueous copper sulphate solution (CuSO4) is electrolysed with copper electrodes.
(c) The moist starch iodide paper turns blue-black when exposed to chlorine gas.
(d) When calcium hydroxide is heated with ammonium chloride crystals, the pungent smelling gas (ammonia) is given out.