Some reactions of two ores, A₁ and A₂ of the metal M are given below.

(see attachement)

Identify A₁, A₂, M, C, D, and G, and explain using the required chemical reactions.

Calcinations of the ore A₁ to form CO₂ indicates that A₁ should be a carbonate. Further, reaction of A₁ with HCI and KI to evolve I₂ indicates that A_­1 would also be hydroxide. So the possible formula for the ore, should be CuCO₃.Cu(OH)₂ which explains all the given reactions

CuCO₃.Cu(OH)₂ 2CuO ↓ +CO₂ + H₂O

(A₁) (C) black

CuCO₃.Cu(OH)₂ + 4HCI → 2CuCI₂ + CO₂ + 3H₂O

(A₁)

2CuCI₂ + 4KI → Cu₂ ↓ + 4KCI + I₂

(D)

Roasting of A₂ gives gas G whose nature is identified as SO₂ as it gives green colour with acidified K₂Cr₂O₇. So A₂ should be sulphide of copper.

2Cu₂S + 3O₂ 2Cu₂O + 2SO₂

(A₂) (G)

Cu₂S + 2Cu₂O 6Cu+SO₂

(M)

3SO₂ + K₂Cr₂O₇ + H₂SO₄ → K₂SO₄ + Cr₂(SO₄)₃ + 4H₂O