3.1.6 – Strong and weak acids and bases
📌 Strength of an acid/base is relative to extent of ionisation
- The strength of an acid is dependent on it’s extent of ionisation
- Strong acids are defined as those that can completely dissociate while weak acids only partially dissociate
- Most organic acids are considered to be ‘weak acids’ while acids like HCl are known as strong acids
- Similarly, bases are defined as strong or weak depending on how easily ionised they are
⭐️ remember not to confuse concentration with strength of an acid
a highly concentrated acid can still be weak
- The ease of dissociation is based on the strength of the bond between the hydrogen atom and the atom ‘X’
- For example, the strength of hydrogen halides increases down the group BECAUSE the bond strength decreases down the group
📌 Strong and weak acid/base properties
- Strong acids and bases are better conductors of electricity than weak acids and bases (assuming the same concentrations are compared)
- Strong acids and bases increase the rate of reaction while reactions will be slower with weaker acids/bases
- Strong acids have lower pH than weak acids (all below 7) and strong bases have high pH than weak bases (all above 7)