Ionisable and non-ionisable compounds
An ionisable compound when dissolved in water or in its molten state, dissociates into ions almost entirely. Example: NaCl, HCl, KOH, etc.
A non-ionisable compound does not dissociate into ions when dissolved in water or in its molten state. Example: glucose, acetone, etc.
Acids and Bases
An acid is any hydrogen-containing substance that is capable of donating a proton (hydrogen ion) to another substance. A base is a molecule or ion able to accept a hydrogen ion from an acid. Acidic substances are usually identified by their sour taste.
Arrhenius theory of acids and bases
Arrhenius acid – when dissolved in water, dissociates to give H+ (aq) or H3O+ ion.
Arrhenius base – when dissolved in water, dissociates to give OH− ion.
Examples
Acids
- Hydrochloric acid (HCl)
- Sulphuric acid (H2SO4)
- Nitric acid (HNO3)
Bases
- Sodium hydroxide (NaOH)
- Potassium hydroxide (KOH)
- Calcium hydroxide (Ca(OH)2)
Bronsted Lowry theory
A Bronsted acid is an H+ (aq) ion donor.
A Bronsted base is an H+ (aq) ion acceptor.
Example
In the reaction: HCl (aq) + NH3 (aq) → NH+4(aq) + Cl− (aq)
HCl – Bronsted acid and Cl− : its conjugate acid
NH3 – Bronsted base and NH+4 : its conjugate acid