How do strong and weak acids differ in proton transfer?

Strong acids fully ionise and transfer all their protons in solution, while weak acids only partially ionise, transferring some protons.

Strong and weak acids differ significantly in their ability to transfer protons, which is a key aspect of their chemical behaviour. Strong acids, such as hydrochloric acid (HCl), sulphuric acid (H2SO4), and nitric acid (HNO3), are fully ionised in aqueous solution. This means that they dissociate completely into their constituent ions, releasing all their hydrogen ions (protons) into the solution. This complete ionisation is what makes these acids 'strong' and gives them a high level of reactivity.

On the other hand, weak acids, like ethanoic acid (CH3COOH) and carbonic acid (H2CO3), only partially ionise in solution. This means that only a small proportion of the acid molecules dissociate to release their hydrogen ions. The majority of the acid molecules remain intact, which results in a lower concentration of hydrogen ions in the solution. This partial ionisation is what makes these acids 'weak'.

The degree of ionisation of an acid in solution is a key factor in determining its acidity. The more an acid ionises, the more hydrogen ions it releases, and the more acidic the solution becomes. Therefore, strong acids, which fully ionise, produce more hydrogen ions and are more acidic than weak acids, which only partially ionise.

The difference in proton transfer between strong and weak acids also affects their reactivity. Strong acids, due to their full ionisation and high concentration of hydrogen ions, are more reactive than weak acids. They can react more readily with other substances, making them more effective in chemical reactions. Conversely, weak acids, due to their partial ionisation and lower concentration of hydrogen ions, are less reactive.