Question

What is the base in `HCl + KOH -> H_2O + KCl`?

Answer 1

`"KOH"`

Explanation:

A base is something which reacts with `"H"^+`.

`"KOH"` dissociates in water to form `"K"^+` and `"OH"^-`.

The `"OH"^-` reacts with `"H"^+` to form `"H"_2"O"`.

Answer 2

The base is potassium hydroxide, which acts as the electron-pair DONOR.

Explanation:

In water we conceive of an acid as `H^+`, or `H_3O^+`, which is our REPRESENTATION of the characteristic cation of the solvent, which accepts electron density (an electron pair) from a base. Hydroxide anion, `HO^-`, is the characteristic anion of the solvent, and an electron pair donor. These species are conceptual rather than actual, nevertheless when we write these entities in equations they are useful for calculation.

Note that the equation you have written is the typical acid base reaction:

`"Acid + Base"` `rarr` `"Salt and Water"`. Which reagent is which?