Question

How do you balance $\mathrm{Mg}+{\mathrm{HNO}}_3\to \mathrm{Mg}{\left({\mathrm{NO}}_3\right)}_2+{\mathrm{H}}_2$

Answer 1

Steps for balancing a chemical reaction:

1. To balance a chemical equation, the stoichiometric coefficients on the reactants and product sides must be equal. The chemical equation follows the rule of conservation of mass and momentum.
2. Write an unbalanced equation for the chemical reaction.
3. Balancing the number of atoms other than hydrogen and oxygen.
4. Balancing hydrogen and oxygen at last because they occur in multiple compounds.

The reaction of formation of Magnesium nitrate:

1. Magnesium reacts with nitric acid to form magnesium nitrate along with hydrogen gas.$\underset{\mathrm{Magnesium}}{\mathrm{Mg}\left(\mathrm{s}\right)}+\underset{\mathrm{Nitric}\mathrm{acid}}{{\mathrm{HNO}}_3\left(\mathrm{l}\right)}\to \underset{\mathrm{Magnesium}\mathrm{nitrate}}{\mathrm{Mg}{\left({\mathrm{NO}}_3\right)}_2\left(\mathrm{s}\right)}+\underset{\mathrm{Hydrogen}\mathrm{gas}}{{\mathrm{H}}_2\left(\mathrm{g}\right)}$
2. Magnesium is already balanced on the reactant and product side.
3. Balancing nitrogen by multiplying ${\mathrm{HNO}}_3$ by$2$, we get $\underset{\mathrm{Magnesium}}{\mathrm{Mg}\left(\mathrm{s}\right)}+\underset{\mathrm{Nitric}\mathrm{acid}}{2{\mathrm{HNO}}_3\left(\mathrm{l}\right)}\to \underset{\mathrm{Magnesium}\mathrm{nitrate}}{\mathrm{Mg}{\left({\mathrm{NO}}_3\right)}_2\left(\mathrm{s}\right)}+\underset{\mathrm{Hydrogen}\mathrm{gas}}{{\mathrm{H}}_2\left(\mathrm{g}\right)}$
4. Oxygen and hydrogen get automatically balanced by balancing nitrogen.

Therefore, the balanced reaction for the formation of magnesium nitrate is $\underset{\mathrm{Magnesium}}{\mathrm{Mg}\left(\mathrm{s}\right)}+\underset{\mathrm{Nitric}\mathrm{acid}}{2{\mathrm{HNO}}_3\left(\mathrm{l}\right)}\to \underset{\mathrm{Magnesium}\mathrm{nitrate}}{\mathrm{Mg}{\left({\mathrm{NO}}_3\right)}_2\left(\mathrm{s}\right)}+\underset{\mathrm{Hydrogen}\mathrm{gas}}{{\mathrm{H}}_2\left(\mathrm{g}\right)}$