Question

All of the following can be used to define a base except

a hydronium ion donor in a reaction
a substance that increases the concentration of hydroxide ions
an electron pair donor in a reaction
a substance that is a hydrogen ion acceptor in a reaction

Answer 1

A base is not defined as a substance that donates hydronium ions, it donates hydroxide ions. The first option is correct.

Answer 2

Answer: The correct statement is a hydronium ion donor in a reaction.

Step-by-step explanation:

According to Arrhenius concept, a base is defined as a substance which donates hydroxide ions
`(OH^-)` when dissolved in water and an acid is defined as a substance which donates hydronium ions
`(H_3O^+)` in water.

According to the Bronsted Lowry conjugate acid-base theory, an acid is defined as a substance which donates protons and a base is defined as a substance which accepts protons.

According to the Lewis concept, an acid is defined as a substance that accepts electron pairs and base is defined as a substance which donates electron pairs.

A substance that increases the hydroxide ion concentration of a solution is an Arrhenius base.

Hence, the correct statement is a hydronium ion donor in a reaction.