A student took Sodium Sulphate solution in a test tube and added Barium Chloride solution to it. He observed that an insoluble substance has formed. The colour and molecular formula of the insoluble substance is:

1. Grey, Ba₂SO₄
2. Yellow, Ba(SO₄)₂
3. White, BaSO₄
4. Pink, BaSO₄

Study the diagram given below and identify the gas formed in the reaction.

1. Carbon di-oxide which extinguishes the burning candle.
2. Oxygen due to which the candle burns more brightly.
3. Sulphur dioxide which produces a suffocating smell.
4. Hydrogen which while burning produces a popping sound.

Sodium reacts with water to form sodium hydroxide and hydrogen gas. The balanced equation which represents the above reaction is

1. Na(s) + 2H₂O(l) ⟶ 2NaOH(aq) + 2H₂(g)
2. 2Na(s) + 2H₂O(l) ⟶ 2NaOH(aq) + H₂(g)
3. 2Na(s) + 2H₂O(l) ⟶ NaOH(aq) + 2H₂(g)
4. 2Na(s) + H₂O(l) ⟶ 2NaOH(aq) + 2H₂(g)

Which of the options in the given table are correct?

1. (i) and (ii)
2. (i) and (iv)
3. (ii) and (iii)
4. (iii) and (iv)