ACIDS

A hydrogen-containing compound which gives hydrogen ions (H₃O⁺ or H⁺) when dissolved in water, is called an acid.

 

Acids can be classified as:

v Naturally-occurring acids

v Mineral acids

 

Mineral acids can be classified into two groups:

Hydracids – The solutions of compounds of hydrogen with highly electronegative (nonmetallic) elements other than oxygen, are called hydracids.

 

Oxoacids – The acids which contain an oxygen-containing anion (called oxoanion), are called oxoacids (earlier called oxyacids).

 

Thus, oxoacids are the compounds which contain hydrogen, oxygen and another nonmetallic element.

 

Strong and Weak Acids

Strong Acids – Acids which are completely ionised/dissociated when dissolved in water are called strong acids.

Example:

Sulphuric acid (H₂SO₄)

Hydrochloric acid (HCl)

Perchloric acid (HClO₄)

 

Weak  Acids  – Acids which are partially ionised when dissolved in water are called weak acids.

Example:

Ethanoic acid (CH₃COOH)

Carbonic acid (H₂CO₃)

Hydrocyanic acid (HCN)