consider the chemical reaction below.\n\nzn(s) + 2h+(aq) → zn2+(aq) + h2(g)\n\nwhich half - reaction…
consider the chemical reaction below.\n\nzn(s) + 2h+(aq) → zn2+(aq) + h2(g)\n\nwhich half - reaction correctly represents reduction for this equation?\no zn(s) → zn2+(aq) + 2e-\no 2h+(aq) + 2e- → h2(g)\no zn(s) → zn2+(aq) + e-\no 2h+(aq) + e- → h2(g)
Answer
Explanation:
Step1: Recall reduction definition
Reduction is gain of electrons.
Step2: Analyze half - reactions
In the reaction $2H^{+}(aq)+2e^{-}\longrightarrow H_{2}(g)$, hydrogen ions gain electrons to form hydrogen gas. In $Zn(s)\longrightarrow Zn^{2 +}(aq)+2e^{-}$ and $Zn(s)\longrightarrow Zn^{2 +}(aq)+e^{-}$, zinc loses electrons (oxidation). Also, $2H^{+}(aq)+e^{-}\longrightarrow H_{2}(g)$ is not a balanced half - reaction as the number of electrons is not consistent with the change in oxidation state.
Answer:
$2H^{+}(aq)+2e^{-}\longrightarrow H_{2}(g)$