Question

Review this balanced neutralization reaction: `HBr + KOH = KBr + H_2O`. Which substance is the base?

Answer 1

`KOH`

Explanation:

We know that a neutralization reaction is as follows:

`"acid + base" \ -> \ "salt + water"`

Here, we got:

`HBr+KOH->KBr+H_2O`

Usually, we use the Bronsted-Lowry acid-base theory, but here, we cannot use it, as we do not know which substance donated the hydrogen ion or which substance received it.

And so, we can use the simplified version of the Bronsted-Lowry theory, the Arrhenius theory.

It states that acids dissociate into `H^+` ions in aqueous solutions, while bases dissociates into `OH^-` ions in aqueous solutions.

From here, we see that potassium hydroxide `(KOH)` has a `K^+` cation and a `OH^-` anion, and will so dissociate into those two ions in an aqueous solution.

Thus, `KOH` is the base.