Identify the metallic oxide which is amphoteric in nature :

1. Calcium oxide
2. Barium oxide
3. Zinc oxide
4. Copper (II) oxide.

In the given equation identify the role played by concentrated sulphuric acid.

S + 2H₂SO₄ ⟶ 3SO₂ + 2H₂O

1. Non-volatile acid
2. Oxidising agent
3. Dehydrating agent
4. None of the above

Which of the following is not a typical property of an ionic compound?

1. High melting point.
2. Conducts electricity in the molten and in the aqueous solution state.
3. They are insoluble in water.
4. They exist as oppositely charged ions even in the solid state.

The metals zinc and tin are present in the alloy :

1. Solder
2. Brass
3. Bronze
4. Duralumin.