- 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.