Question

the coefficient of fe^{3+} in the balanced version of al + fe^{3+} → al^{3+} + fe^{2+} is
1
3
5
7

Explanation:

Step1: Determine oxidation states and electron transfer

• Oxidation state of \(Al\) changes from \(0\) to \(+3\), so \(Al\) loses \(3e^-\) (\(Al

ightarrow Al^{3 +}+3e^-\)).

• Oxidation state of \(Fe^{3+}\) changes to \(Fe^{2+}\), so \(Fe^{3+}\) gains \(1e^-\) (\(Fe^{3 +}+e^-

ightarrow Fe^{2+}\)).

Step2: Balance electrons

• To balance electrons, multiply the \(Fe^{3 +}+e^-

ightarrow Fe^{2+}\) half - reaction by \(3\) to make electrons lost equal to electrons gained.

The balanced equation is \(Al + 3Fe^{3+}
ightarrow Al^{3+}+3Fe^{2+}\)

Answer:

\(3\)