Chapter EH, Problem 43R

Solution

Interpretation: A balanced chemical equation for the given reaction needs to be determined.

Concept Introduction: A chemical reaction is said to be balanced if its equation has an equal number of atoms of the same elements on both sides of the reaction arrow. Any reaction can be balanced by giving suitable stoichiometric coefficients to the reactants and products in the reaction.

  ${\text{10KClO}}_{\text{3}}+3{\text{P}}_4\to 10\text{KCl}+3{\text{P}}_{\text{4}}{\text{O}}_{\text{10}}$

According to the question, potassium chlorate reacts with red phosphorus to produce potassium chloride and phosphorus pentoxide.

The given reaction can be represented as follows:

  ${\text{KClO}}_{\text{3}}+{\text{P}}_4\to \text{KCl}+{\text{P}}_{\text{4}}{\text{O}}_{\text{10}}$

Check the number of atoms of each element in the above equation.

Elements	Number of atoms reactant side	Number of atoms product side
K	1	1
Cl	1	1
O	3	10
P	4	4

Here, the number of oxygen atoms is not the same. To balance the number of oxygen atoms give coefficients 10 to ${\text{KClO}}_{\text{3}}$ and 3 to ${\text{P}}_{\text{4}}{\text{O}}_{\text{10}}$ in the above reaction.

  ${\text{10KClO}}_{\text{3}}+{\text{P}}_4\to \text{KCl}+3{\text{P}}_{\text{4}}{\text{O}}_{\text{10}}$

Now, give coefficient 10 to KCl and 3 to ${\text{P}}_4$ to balance, K, Cl, and P atoms.

  ${\text{10KClO}}_{\text{3}}+3{\text{P}}_4\to 10\text{KCl}+3{\text{P}}_{\text{4}}{\text{O}}_{\text{10}}$

Therefore, the balanced chemical equation is as follows:

  ${\text{10KClO}}_{\text{3}}+3{\text{P}}_4\to 10\text{KCl}+3{\text{P}}_{\text{4}}{\text{O}}_{\text{10}}$