Question

What is the difference between a strong acid and a weak acid as well as a strong base versus a weak base with regards to ionization?

Answer 1

Strong acids and bases virtually completely ionise in an aqueous solution.

Explanation:

Let's look at the Bronsted-Lowry definition of acids and bases:

• Acids donate `H^+` ions to an aqueous solution.
• Bases accept `H^+` ions in an aqueous solution.

Strong acids like `HCl` will virtually completely dissociate, or ionize, into ions when in an aqueous solution:

`HCl(aq) -> H^+(aq) + Cl^(-)(aq)`

Weak acids, like acetic acid (`CH_3COOH`), will not ionize to the extent that strong acids do, although it does somewhat ionise and this reaction will occur:

`CH_3COOH(aq) ⇌ H^+(aq) + CH_3COO^(-)(aq)`

Strong bases, like `NaOH`, will also virtually completely ionise, or dissociate, into ions in an aqueous solution.

`NaOH(aq) -> OH^-(aq) + Na^+(aq)`

Weak bases, like `NH_3`, like weak acids, will dissociate only very slightly in an aqueous solution. The below reaction will occur, but it will be rare.

`NH_3(aq) ⇌ OH^(-)(aq) + NH_4^+(aq)`