Question

Give balanced equation for each of the following: Oxidation of carbon with concentrated nitric acid:

Answer 1

Hint: During oxidation of carbon, carbon dioxide gas is formed. Nitric acid on reduction forms nitrogen dioxide. By counting down the number of each atoms present on reactant as well as product side, we can balance as each atom must be same in quantity on both si.

Complete Step by step answer: Oxidation of carbon with concentrated nitric acid forms carbon dioxide, nitrogen dioxide and water:
We have to write an unbalanced chemical equation for the oxidation of carbon with concentrated nitric acid.
\[{\text{C}}\left( s \right){\text{ + HN}}{{\text{O}}_3}\left( {aq} \right){\text{ }} \to {\text{ C}}{{\text{O}}_2}\left( g \right){\text{ + N}}{{\text{O}}_2}\left( g \right){\text{ + }}{{\text{H}}_2}{\text{O}}\left( l \right)\]
One carbon atom is present on the reactant side. One carbon atom is present on the product side. Hence, the carbon atoms are balanced on both sides of the equation.
One nitrogen atom is present on the reactant side. One nitrogen atom is present on the product side. Hence, the nitrogen atoms are balanced on both sides of the equation.
One hydrogen atom is present on the reactant side. Two hydrogen atoms are present on the product side. Hence, the hydrogen atoms are NOT balanced on both sides of the equation.
Three oxygen atoms are present on the reactant side. Five oxygen atoms are present on the product side. Hence, the oxygen atoms are NOT balanced on both sides of the equation.
To balance hydrogen and oxygen atoms, multiply water with 2, nitric acid with 4 and nitrogen dioxide with 4.
\[{\text{C}}\left( s \right){\text{ + 4 HN}}{{\text{O}}_3}\left( {aq} \right){\text{ }} \to {\text{ C}}{{\text{O}}_2}\left( g \right){\text{ + 4 N}}{{\text{O}}_2}\left( g \right){\text{ + 2 }}{{\text{H}}_2}{\text{O}}\left( l \right)\]
This is the balanced chemical equation for the oxidation of carbon with concentrated nitric acid to form carbon dioxide, nitrogen dioxide and water.

Note: When carbon atom is oxidized to carbon dioxide gas, the oxidation number of carbon increases from 0 to +4. When nitric acid is reduced to nitrogen dioxide, the oxidation number of nitrogen decreases from +5 to +4.