How is an acid prepared from a (a) Non-metal (b) salt ? Give an equation for each.

(a) Preparation of an Acid from a Non-metal:

Non-metals react with oxygen to form non-metal oxides. These non-metal oxides react with water to form acids. For example, sulfur is a non-metal. It reacts with oxygen to form sulfur dioxide. Sulfur dioxide then reacts with water to form sulfurous acid.

Equation: S(s) + O2(g) -> SO2(g) SO2(g) + H2O(l) -> H2SO3(aq)

(b) Preparation of an Acid from a Salt:

Acids can be prepared from salts by the process of acid hydrolysis. In this process, a salt reacts with water to form an acid and a base. For example, ammonium chloride is a salt. It reacts with water to form hydrochloric acid and ammonia.

Equation: NH4Cl(s) + H2O(l) -> HCl(aq) + NH3(g)