General Chemistry 2: Electrochemistry

The following reaction takes place under acidic conditions. Assign oxidation numbers and balance the oxidation reduction reaction using the half reaction method.

HNO$_3$ + Fe$^{2+}$ $\longrightarrow$ Fe$^{3+}$ + NO$_2$

Balance the following redox reaction given acidic conditions, using the half reaction method.

$S (s) + NO_2^+ (aq) \longrightarrow SO_2^- (aq) + NO (g)$ .

What is the standard free energy change, $\triangle G ^\circ$ for the following reaction at 25$^\circ$

$Cu ^{2+} (aq) + Fe (s) \longrightarrow Cu (s) + Fe ^{2+} (aq)$