Amongst the various ores of a metal (M) (sulphide, carbonates, oxides, hydrated or hydroxides) two ores [X] and [Y] show the following reactivity. (i)
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 gives a 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_2O to 6Cu+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 metal ores [X] and [Y] are respectively :
A. Carbonate and sulphide ores
B. Sulphide and carbonate ores
C. Carbonate and hydroxide ores
D. Carbonate and oxide ores
1 Answers
Correct Answer - A
`[X]=CuCO_3 Cu(OH)_2 or 2CuCO_3. Cu(OH)_2 , [Y]=Cu_2S or CuFeS_2`