(i) Give a balanced chemical equation for each of the following:

1. Reaction with one reactant forming three products.
2. Reaction with two reactants forming two products.
3. Reaction with two reactants forming three products.

(ii) Give a balanced chemical equation for the following word equation:

Potassium dichromate reacts with sulphuric acid and sulphur dioxide to form potassium sulphate, chromium (III) sulphate and water.

How will you distinguish between the following:

(i) Carbon dioxide gas and sulphur dioxide gas.

(ii) Hydrogen gas and hydrogen chloride gas?

(i) Name the process used to manufacture Hydrogen.

(ii) Write all the reactions involved (with proper conditions).

The question refers to the elements of the periodic table with atomic numbers from 3 to 18. In the table below, the elements are shown by letters which are not indicative of the usual symbols of the elements.

Which of these is :

1. a noble gas ?
2. a halogen ?
3. an element with valency 4 ?