Which gas decolourises potassium permanganate (KMnO₄) solution?

1. Sulphur dioxide
2. Ammonia
3. Hydrogen chloride
4. Carbon dioxide

The metal whose oxide can be reduced by common reducing agents:

1. Copper
2. Sodium
3. Aluminium
4. Potassium

An organic compound has a vapour density of 22. The molecular formula of the organic compound is: [Atomic weight: C = 12, H = 1]

1. CH₄
2. C₂H₄
3. C₂H₆
4. C₃H₈

In the reaction given below sulphuric acid acts as a/an:

S + 2H₂SO₄ ⟶ 3SO₂ + 2H₂O

1. Non-volatile acid
2. Dibasic acid
3. Oxidising agent
4. Reducing agent