Answer to Question #341898 in General Chemistry for Kaye

Question

Balance the following redox reaction that takes place in an acidic solution using the oxidation number method: Fe203(s)+CO(g)-Fe3(aq)+Cr3+(aq)

Answer 1

$Fe_2O_3{(s)}+3CO_{(g)} \rightarrow 2Fe _{(s)}. + 3CO_{2(g)}$

$Fe^{+3}-3e \rightarrow Fe^0 (1)$

$C^{+2} +2 e\rightarrow C^{+4} (2)$

So we should multiply reaction 1 on 2, and reaction 2 on 3.