i. An Arrhenius acid is a substance which furnishes hydrogen ions (H+ ions) in aqueous solution,
HCI →H+ + CI- (strong acid)
CH3 COOH ⇌ CH3 COO + H+ (weak acid)
ii. An Arrhenius base is a substance which furnishes hydroxyl (OH-) ions in aqueous solution, e.g.,
NaOH →Na+ + OH- (strong base)
NH4 OH ⇌ NH4+ + OH- (weak base)
iii. The strength of an acid or base depends upon its tendency to furnish H+ or OH- ions in solution, respectively.
iv. Water is amphoteric because it furnishes both H+ and OH- ions in solution
H2O ⇌ H+ + OH-