Table to compare acid base theories.
Acid-base theory |
Definition of acid |
Acid example |
Definition of base |
Base example |
|---|---|---|---|---|
Arrhenius |
It is any species that increases the concentration of H⁺ in an aqueous solution. H⁺ ions react immediately with H₂O to form hydronium ions (H₃O⁺). |
HCl(ac)→H+(ac)+ Cl–(ac) |
It is any species that increases the concentration of OH- in an aqueous solution. |
NaOH(ac)→ Na+(ac)→OH–(ac) |
Brønsted-Lowry |
It is any species capable of donating a proton, H⁺. * Water is defined as an amphoteric substance as it can act as an acid or a base. * * Conjugated acid is the species that is formed when a Brønsted-Lowry base accepts a proton. * |
NH3(g)+HCl (g) → NH4Cl (s) * Also expressed as  * Conjugated acid  |
It is any species capable of accepting a proton, which requires a lone pair of electrons to bond to H+. * Conjugate base is the species that forms after a Brønsted-Lowry acid donated a proton. * |
NH3(ac)+H2OR(l⇌NH4+(ac) + OH–(ac) * Conjugate base OH–(ac) |
Lewis |
It is a chemical species capable of accepting and sharing a pair of electrons given up by a base. |
Acid + Base → adduct H++ : NH3 |
It is a chemical species capable of giving up a pair of electrons and sharing them with an acid. |
Acid + Base → adduct  |
Examples of acid-base reactions according to different theories.
Reaction |
Arrhenius |
Brønsted-Lowry |
Lewis |
Commentary |
|---|---|---|---|---|
HCl + NaOH → NaCl + H2O |
Acid + Base → Salt + Water
HCl + NaOH → NaCl + H2O |
Acid + Base → Conj base + Conj acid.
HCl + NaOH → NaCl + H2O |
Acid + Base → adduct
HCl + NaOH → NaCl + H2O |
|
H2PO4– + HCl → H3PO4 + Cl– |
Does not apply |
Acid + Base → Conj acid. + Conj base
H2PO4– + HCl → H3PO4 + Cl– |
Acid + Base → adduct
H2PO4– + HCl → H3PO4 + Cl– |
* Arrhenius theory does not apply because an OH ion is necessary for definition. |
AlCl3 + NH3 → [Al (NH3) Cl3] |
Does not apply |
Does not apply |
Acid + Base → adduct
AlCl3 + NH3 → [Al (NH3) Cl3] |
* Everyone Brønsted-Lowry acids and bases they are Lewis acids and bases, but not all Lewis acids and bases are Brønsted-Lowry. |
