A chemical base may be defined as a compound which contributes
when dissolved in water

Hydroxide ion (OH^-)

Explanation:

A base is a substance which dissolves in water to produce hydroxide ion(OH^-) as the only negative ion. Thus, a base will contribute OH^- when dissolve in water. For instance, NaOH is a strong base and we give out OH^- when dissolve in water as shown below:

NaOH <==> Na^+ + OH^-

h let me think

- decrease the number of plants and animals living in the water.