Question

an acid is a substance that increases the concentration of h₃o⁺ ions in solution. look at the reaction below of phenol (c₆h₅oh) with water: c₆h₅oh(aq) + h₂o(l) —→ c₆h₅o⁻(aq) + h₃o⁺(aq) which reactant acts as an acid by contributing a h⁺ ion to create h₃o⁺ in the chemical equation? ☐ c₆h₅oh(aq) ☐ h₂o(l) ☐ c₆h₅o⁻(aq) ☐ h₃o⁺(aq)

Explanation:

To determine which reactant acts as an acid (donates $\ce{H+}$ to form $\ce{H3O+}$), we analyze the reaction: $\ce{C6H5OH(aq) + H2O(l) -> C6H5O-(aq) + H3O+(aq)}$. An acid donates a proton ($\ce{H+}$). In this reaction, $\ce{C6H5OH(aq)}$ loses a $\ce{H+}$ (becomes $\ce{C6H5O-}$) and that $\ce{H+}$ combines with $\ce{H2O}$ to form $\ce{H3O+}$. $\ce{H2O(l)}$ is the base here (accepts $\ce{H+}$), $\ce{C6H5O-(aq)}$ is the conjugate base, and $\ce{H3O+(aq)}$ is the conjugate acid. So the reactant acting as an acid by contributing $\ce{H+}$ is $\ce{C6H5OH(aq)}$.

Answer:

A. $\ce{C6H5OH(aq)}$