The reason why acids are so harmful is because in their aqueous state, hydrogen is ionised into H3O+ (an hydronium ion).
Strong acids, such as hydrochloric acid (HCl), ionise completely, with every H atoms ionising into hydronium.
Weak acids, such as acetic acid (CH3COOH), only partially ionise in water forming H3O+ and CH3COO-
Most importantly, acids are ALWAYS written as aqueous and NOT solid - in their solid state they are not classified as acids.
We will learn more about the ionisation of acids in Module 6 - right now the following is all you need to know.
EXAMPLE:
CH3COOH (aq) ⇋ H3O+ (aq) + CH3COO- (aq)
1. Calculate Ka as you would Keq
A large Ka (and therefore a larger numerator) the greater the concentration of ions compared to the acid - therefore, greater the degree of ionisation.
pH (potential hydrogen) is the measure of the concentration of hydronium ions in a solution.