Question

Bases when dissolved in water produce ________________.

Answer 1

An acid or a base is able to dissociate in water to produce their respective ions. The capacity of their dissociation in solutions determines the strength of any acid or a base. If it is strong then it will produce more of the ions that are contained in it. The type of the ions produced can be identified by various theories of acids and bases.

Complete answer:
An acid and a base are capable of being dissolved in water to dissociate into their respective ions. The type of ions produced can be told by the definition of acids and bases according to the Arrhenius theory of acids and bases.
According to the Arrhenius concept of acids and bases, acids are the substances that can give a hydrogen ion or a proton $\left( {{H}^{+}} \right)$ in solutions. While bases are the substances that can give hydroxide ions that are $O{{H}^{-}}$ ions in any solution. Arrhenius acids are HCl, HCN, etc, while Arrhenius bases are NaOH, KOH, etc.
Hence, Bases when dissolved in water produce hydroxide or $O{{H}^{-}}$ ions.

Additional information:
The production of the hydrogen and the hydroxide ions in any solution determines the strength of an acid and base respectively. It is determined as dissociation constant for an acid ${{K}_{a}}$ in case of acids, and the dissociation constant of a base ${{K}_{b}}$ in terms of a base. Greater the value of dissociation constants of acids and bases stronger is the acid and the base.

Note:
There are substances that do not have hydrogen or hydroxide ions, still they are considered as acids and bases. Like acids without hydrogen ion is $S{{O}_{2}},N{{O}_{3}}$, etc. While bases without hydroxide are $N{{H}_{3}},N{{a}_{2}}C{{O}_{3}},CaO$, etc. but their solutions in water can produce hydrogen and hydroxide ions, so they are acids and bases.