Calculations involving acids and bases

Most acidic and basic substances are weak and are therefore partially ionized in aqueous solution. Chemists can therefore use the equilibrium law to represent the extent to which a weak acid or base ionizes or dissociates. 

For example, for a weak acid the equilibrium can be represented in either of the following ways, depending on whether the hydrated proton is represented as H30 (oxonium) or H  

Because water is a solvent, it is omitted from the equilibrium expression, which can be written 

The acidity of oxyacids increases with increasing eiectronegativity of the haiogen atom 

The magnitude (size) of indicates the tendency of the acid to ionize or dissociate in water. The larger the value of K, the stronger the acid. pfC = -logjofCg is another measure of acid strength. The smaller the value of pK, the stronger the acid. 

---