Match List-I and List-II:
List-I                                                       List-II
a. Haematite                                           i. Al$$_2$$O$$_3$$ . xH$$_2$$O
b. Bauxite                                               ii. Fe$$_2$$O$$_3$$
c. Magnetite                                           iii. CuCO$$_3$$ . Cu(OH)$$_2$$
d. Malachite                                            iv. Fe$$_3$$O$$_4$$
Choose the correct answer from the options given below:

We match each ore with its correct chemical formula.

(a) Haematite is an iron ore with the formula $$\text{Fe}_2\text{O}_3$$, which matches (ii).

(b) Bauxite is an aluminium ore with the formula $$\text{Al}_2\text{O}_3 \cdot x\text{H}_2\text{O}$$, which matches (i).

(c) Magnetite is an iron ore with the formula $$\text{Fe}_3\text{O}_4$$, which matches (iv).

(d) Malachite is a copper ore with the formula $$\text{CuCO}_3 \cdot \text{Cu(OH)}_2$$, which matches (iii).

Therefore, the correct matching is (a)-(ii), (b)-(i), (c)-(iv), (d)-(iii).