Question

the reaction below was carried out in an acidic solution.
\text{i}^- + \text{io}_3^- longrightarrow \text{i}_2
which statement is true about this equation?
\begin{array}{l} \bigcirc \text{although it is unbalanced, it can be balanced by using the half-reaction method.} \\ \bigcirc \text{it has been balanced by using the half-reaction method.} \\ \bigcirc \text{it has been balanced by directly using spectator ions.} \\ \bigcirc \text{although it is unbalanced, it can be balanced by directly using spectator ions.} end{array}

Explanation:

1. First, analyze the given reaction $\ce{I^- + IO_3^- -> I_2}$. Check the number of atoms and charges:

• For I atoms: Left side has 1 (from $\ce{I^-}$) + 1 (from $\ce{IO_3^-}$) = 2, right side has 2 (from $\ce{I_2}$), so I atoms seem balanced in count, but we also need to check O and H (since it's acidic solution) and charges.
• The reaction is in acidic solution, so we need to balance O with $\ce{H_2O}$ and H with $\ce{H^+}$, and also balance charges with electrons. The half - reaction method is suitable for redox reactions (this is a redox reaction as I has different oxidation states: - 1 in $\ce{I^-}$, + 5 in $\ce{IO_3^-}$, and 0 in $\ce{I_2}$).
• Spectator ions are used in reactions with ionic compounds in solution where some ions don't participate in the reaction. In this redox reaction, there are no spectator ions involved in the redox process, and the reaction as given is unbalanced (we need to balance O, H, and charges). So the correct statement is that although it is unbalanced, it can be balanced by using the half - reaction method.

Answer:

A. Although it is unbalanced, it can be balanced by using the half - reaction method