Question

Reaction of \[B{r_2}\] with \[N{a_2}C{O_3}\]in aqueous solution gives sodium bromide and sodium bromate with evolution of \[C{O_2}\]​gas. The number of sodium bromide molecules involved in the balanced chemical equation is:
A: 5
B: 4
C: 10
D: 2.5

Answer 1

Hint: Stoichiometry depicts the relation between the amount of reactants as well as products in a chemical reaction. It is actually the quantitative relationship between the number of moles (and thus mass) of different reactants as well as products in a chemical reaction.

Complete step by step answer:
To completely understand a chemical reaction, first of all write a balanced chemical equation. You must balance the chemical reactions by adding coefficients in a manner such that the number of atoms corresponding to each element is similar on each side. The balanced chemical reaction for the given reaction of \[B{r_2}\]​with \[N{a_2}C{O_3}\]​in aqueous solution can be written as follows:
$3N{a_2}C{O_3} + B{r_2} \to 5NaBr + NaBr{O_3} + 3C{O_2}$
Through stoichiometry, 3 moles of Br2 react with 3 moles of \[N{a_2}C{O_3}\]to yield 5 moles of \[NaBr\], 1 mole of \[NaBr{O_3}\]and 3 moles of \[C{O_2}\]gas.
As a result, it is clear that 5 molecules of \[NaBr\]have been generated in the above chemical reaction.

Hence, the correct option is A i.e. 5.

Note:
Chemical equations are actually the symbolic representations of a chemical reaction. Balanced chemical equations only display formulae, not the names. All the atoms in the material/substance following it get multiplied by the balancing number. Balanced chemical equations usually involve state symbols as well in brackets following each formula. They actually depict the physical state or form of that material/substance.