H O + O
H
H Cl H +
H
H Cl−
Base
(proton acceptor)
Acid
(proton donor)
Conjugate
acid of H 2 O
Conjugate
base of HCl
1) Hydrogen chloride, a very strong acid, transfer its proton to water.
2) Water acts as a base and accepts the proton.
- Conjugate acid: the molecule or ion that forms when a base accepts a proton.
- Conjugate base: the molecule or ion that forms when an acid loses its proton.
- Other strong acids:
HI I−
Br Br−
SO 4 HSO 4 −
SO 4 − SO 42 −
+ H 2 OH 3 O+ +
H + H 2 OH 3 O+ +
H 2 + H 2 OH 3 O+ +
H + H 2 OH 3 O+ +
Hydrogen iodide
Hydrogen bromide
Sulfuric acid (~10%)
- Hydronium ions and hydroxide ions are the strongest acid and base that can exist
in aqueous solution in significant amounts.
- When sodium hydroxide dissolves in water, the result is a solution containing
solvated sodium ions and solvated hydroxide ions.
Na+OH−(solid) Na+(aq) + HO(aq)−
Na+
H 2 O
O
O OH
O OH
O −O O
O
O
H 2
H 2 2
H 2 2
H
H
H H
H
H
H
H
H
Solvated sodium ion Solvated hydroxide ion
- An aqueous sodium hydroxide solution is mixed with an aqueous hydrogen
chloride (hydrochloric acid) solution:
