Question

which is the balanced version of the half - reaction below? h2s → s + h+ a. h2s → s + 2h+ + 2e− b. h2s → s + 2h+ c. h2s → s + h+ + e− d. h2s + 2e− → s + 2h+

Explanation:

Step1: Balance hydrogen atoms

In the reactant side, there are 2 hydrogen atoms in $H_2S$. On the product side, to balance hydrogen atoms, we need 2 $H^+$ ions. So the equation becomes $H_2S
ightarrow S + 2H^+$.

Step2: Balance the charge

The left - hand side of the equation $H_2S$ is neutral (charge = 0). The right - hand side has a total charge of + 2 from the two $H^+$ ions. To balance the charge, we need to add 2 electrons ($2e^-$) to the right - hand side. So the balanced half - reaction is $H_2S
ightarrow S + 2H^+ + 2e^-$.

Answer:

A. $H_2S
ightarrow S + 2H^+ + 2e^-$