Acid-Base Reactions

For example:

HCl (g) + NH3(g) NH4+Cl- (s)

Acids and Bases in Solutions

HCl (aq) H+ (aq) + Cl- (aq)

NH3(aq) + H2O (l) NH4+ (aq) + OH-

Acid-base pairs

CH3COOH (aq) CH3COO- (aq) + H+ (aq)

CH3COO- (aq) + H+(aq) CH3COOH(aq)

  • When the acid ion acts as a base, it is called a conjugate base. In the above reaction, the ethanoic ion is the conjugate base of ethanoic acid.
  • Every acid has a conjugate base, and every base has a conjugate acid.
  • We refer to them as conjugate acid-base pairs.
  • The general formula for a conjugate acid-base pair is summarised below.
    HA(aq) H + A-

    Strengths of acids and bases


    Useful books for revision:

    Revise AS Chemistry for Salters (Written by experienced examiners and teachers of Salter's chemistry)
    Revise AS Chemistry for Salters (OCR) (Salters Advanced Chemistry)