Question

Balance the reaction
A. $Ca{(HC{O_3})_2} + HN{O_3} \to Ca{(N{O_3})_2} + {H_2}O + C{O_2}$
B. $C + HN{O_3}[conc.] \to C{O_2} + {H_2}O + N{O_2}$
C. $S + HN{O_3}[conc.] \to {H_2}S{O_4} + {H_2}O + N{O_2}$
D. $Cu + HN{O_3}[conc.] \to Cu{(N{O_3})_2} + {H_2}O + N{O_2}$
D. $C + {H_2}S{O_4}[conc.] \to C{O_2} + {H_2}O + S{O_2}$

Answer 1

Hint: According to the law of conservation of mass, when a chemical reaction occurs, the mass of the product should be equal to that of the reactants. Therefore, the amount of the atoms in each element does not change in the chemical reaction. As a result, the chemical equation that shows the chemical reaction needs to be balanced. Thus, no. of atoms in reactants and products should be equal.

Complete step by step answer:
When balancing the chemical equations, our goal is to have the same number of each type of atom on the reactants and products side of the equation.
A. $Ca{(HC{O_3})_2} + 2HN{O_3} \to Ca{(N{O_3})_2} + 2{H_2}O + 2C{O_2}$
This is a gas evolution reaction and $C{O_2}$ is the formed gas.
B. $C + 4HN{O_3}[conc.] \to C{O_2} + 2{H_2}O + 4N{O_2}$
This is an oxidation-reduction (redox) reaction. C is a reducing agent and $HN{O_3}$ is an oxidising agent.
C. $S + 6HN{O_3}[conc.] \to {H_2}S{O_4} + 2{H_2}O + 6N{O_2}$
This is an oxidation-reduction reaction (redox reaction). Here, S is the reducing agent and $HN{O_3}$ is an oxidising agent.
D. $Cu + 4HN{O_3}[conc.] \to Cu{(N{O_3})_2} + 2{H_2}O + 2N{O_2}$
Copper reacts with nitric acid to produce copper nitrate, nitrogen dioxide and water.
E. $C + 2{H_2}S{O_4}[conc.] \to C{O_2} + 2{H_2}O + 2S{O_2}$
This is an oxidation-reduction (redox) reaction. C is a reducing agent and ${H_2}S{O_4}$ is an oxidising agent.

Note: A balanced chemical equation occurs when the number of the atoms involved in the reactants side is equal to the number of atoms in the product side. The relative numbers of reactants and products are represented by their coefficients.