All of the following can be used to define an acid except

a hydrogen ion donor in a reaction

a substance that increases the hydronium ion concentration of a solution

an electron-pair acceptor in a reaction

a substance that increases the hydroxide ion concentration of a solution

a substance that increases the hydroxide ion concentration of a solution

Explanation: According to Arrhenius concept, an acid is a substance which donates hydronium ions   ions when dissolved in water and base is a substance which donates hydroxide ions ions in water.

According to the Bronsted Lowry conjugate acid-base pair, an acid is a substance that donates protons and a base is a substance that accepts protons.

According to Lewis concept, an acid is the substance which accepts electron pairs and abase is a substance which donates electron pairs.

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

the answer is 0.8m.

by: nicholas

i think its 5049.

i hope this !