Amongst the various ores of a metal (M) (sulphide, carbonates, oxides, hydrated or hydroxides) two ores [X] and [Y] show the following reactivity. (i)[X] on calcination gives a black solid (S), carbon dioxide and water. (ii)[X] Dissolved in dilute HCl, on reaction with Kl gives a white precipitate (P) and iodine. (iii)[Y] on roasting gives metal (M) and a gas (G_(1)) which turns acidified K_2Cr_2O_7 solution green. (iv)[Y] on reaction with dil.HCl givesa white precipitate (Q) and another gas (G_2) which turns lead acetate solution black, and also reacts with gas (G_1) to precipitate colloidal sulphur in presence of moisture. Reaction involved: (i)CuCO_3. Cu(OH)_2oversetDeltatoCuOdarr("black")+CO_2+H_2O CuCO_3.Cu(OH)_2+4HCl to2CuCl_2+3H_2O+CO_2 (ii)2Cu^(2+)+4I^(-)toCu_2l^2 darr (P)("white")+l_2uarr (iii)2Cu_2S+3O_2to2Cu_2O+2SO_2(G_1) Cu_2S+2Cu_2Oto6Cu+SO_2 (iv)Cu_2S+2HCl to 2CuCldarr(Q)("white")+H_2S(G_2) Pb^(2+)+H_2StoPbSdarr("black")+2H^(+) (v)SO_2(G_1)+2H_2S(G_2)overset("moisture")to3Sdarr+2H_2O The white precipitate (P) is of :