The ore that can be concentrated by using magnetic separation:

1. Corundum
2. Haematite
3. Calamine
4. Bauxite

The diagram given below shows the bonding in the covalent molecule AB₂.

Which option represents the correct electronic configuration of atoms A and B before combining together to form the above molecule?

Assertion (A): In the Contact Process SO₃ gas is not directly dissolved in water to obtain sulphuric acid.

Reason (R): Dense fog or misty droplets of sulphuric acid are formed which is difficult to condense.

1. Both (A) and (R) are true, and (R) is the correct explanation of (A).
2. Both (A) and (R) are true, and (R) is not the correct explanation of (A).
3. (A) is true but (R) is false.
4. (A) is false but (R) is true.

Given below are four ions:

Cl^-, Li⁺, Al³⁺, K⁺

Identify the pair of ions which have the same electronic configuration.
[Atomic number: Cl = 17, Li = 3, Al = 13, K = 19]

1. Cl^- & Li⁺
2. Al³⁺ & K⁺
3. Cl^- & K⁺
4. Li⁺ & K⁺