(a) What is a chemical equation?

(b) Why is it necessary to balance a chemical equation?

(c) What are the limitations of a chemical equation?

State the important information obtained from the following in four points:

(a) A molecular formula of a compound.

(b) A balanced chemical equation for a reaction.

State five ways by which a chemical equation can be made more informative.

Given below are two groups showing basic and acid radicals. Based on these two groups, answer the questions that follow :

(a) Which basic radical or cation exhibits variable valency ?

(b) How is NH₄⁺ ion different from other basic radicals in the group ?

(c) Which acid radical or anion is the odd one out in the group ? Justify your answer.

(d) Using one radical from each group, form a compound that is commonly used in daily life. Write its name and chemical formula.