Answer:
The reactant that acts as an acid, by contributing an H⁺ ion to create H3O+ in the chemical equation is C₆H₅OH.
Step-by-step explanation:
According to Brønstend-Lowry, an acid is a substance that transfer a proton (hydrogen cation, H⁺) to a base, forming a base conjugate for the first and an acid conjugate for the second.
From the following reaction:
C₆H₅OH(aq) + H₂O(l) → C₆H₅O⁻(aq) + H₃O⁺(aq)
We have that the C₆H₅OH transfer a proton to the water to form its conjugate base C₆H₅O⁻ and the conjugate acid of water H₃O⁺. Hence, the C₆H₅OH is the acid and the water is the base.
Therefore, the reactant that acts as an acid, by contributing an H⁺ ion to create H3O+ in the chemical equation is C₆H₅OH.
I hope it helps you!