How do you balance #NO_3^(-) + 4H^+ + Pb -> Pb^(2+) + NO_2 + 2H_2O#?
2 units of nitrate ions balanced with 2 units of nitrogen dioxide will provide 6 units of oxygen on both sides of the reaction.
This is a redox equation, and we may separate the oxidation and reduction reactions SEPARATELY in order to balance the equation.
Oxidation: lead metal is oxidized to plumbic ion.
CHARGE and MASS are balanced as is absolutely required.
The final redox equation simply eliminates the electrons: we take
Are charge and mass balanced here? How do you know?