Question

An acid can be defined as

Answer 1

Answer:

b. a proton donor.

Explanation:

An acid can be defined as a substance that produces hydrogen ions or H+ protons when dissolved in water, according to Arrhenius

$HCl -> H^{+} + Cl^{-}$

It, also, can be defined as a molecule or ion which gives or donates a H+ protons when dissolved in water, according to Bronsted y Lowry

$H^{+} + H_{2}O -> H_{3}O^{+}$

And, finally, according to Lewis, an acid can be defined as any compound that can accept a pair of electrons.

Answer 2

An acid can be defined as a proton donor.