- Bases are compounds which react with acid to form a salt and water as only products.
- Bases that soluble in water are called alkalis.
- In aqueous solution, alkali it produces hydroxide ions (OH-). In short, alkalis are substances that form hydroxide ions (OH-(aq)) in water
Sodium hydroxide NaOH gives Na+(aq) and OH-(aq) ions,
NaOH → Na+ + OH-
calcium hydroxide Ca(OH)2 gives Ca2+(aq) and 2OH-(aq) ions.
Ca(OH)2 → Ca2+ + 2OH-
Ammonia give NH4+ and OH-
NH3 + H2O → NH4+ + OH-
[Note: an alkali is a base soluble in water.]
- In alkaline solution there are more OH- ions than H+ ions.