Chapter 17, Problem 10STP

Interpretation Introduction

Interpretation:

The chemical equation is to be balanced.

Concept introduction

A  chemical reaction in which the number of atoms for each element in the reaction and the total charge is the same for both the reactants and the products is called balanced equation.

Answer to Problem 10STP

The balanced equation is

${\text{ PCl}}_{\text{5}}{\text{+ 4H}}_{\text{2}}{\text{O = H}}_{\text{3}}{\text{PO}}_{\text{4}}\text{+ 5HCl}$

Explanation of Solution

The given reaction is

${\text{PCl}}_{\text{5}}{\text{+ H}}_{\text{2}}{\text{O = H}}_{\text{3}}{\text{PO}}_{\text{4}}\text{+ HCl}$

Now, the balanced equation is

${\text{PCl}}_{\text{5}}{\text{+ 4H}}_{\text{2}}{\text{O = H}}_{\text{3}}{\text{PO}}_{\text{4}}\text{+ 5HCl}$

Explanation:

Left side Right side

$\begin{array}{l}\text{P=1 P =1}\hfill \\ \text{Cl =5 Cl =1}\hfill \\ \text{H=2 H=3+1}\hfill \\ \text{O=1 O= 4}\hfill \end{array}$

Now we start balancing the easiest element such as $\text{ Cl}$

Left side Right side

P=1 P = 1

Cl = 5 Cl = 1×5 = 5

H=2 H = 3+ (1×5) = 8

O=1 O = 4

Now equation becomes

PCl₅ + H₂O = H₃PO₄ + 5HCl

Now we balancing the H atom

Left side Right side

$\begin{array}{l}\text{ P=1 P=1}\hfill \\ \text{Cl=5 Cl= 1×5 =5}\hfill \\ \text{H= 2×4 = 8 H= 3+ }\left(\text{1×5}\right)\text{ = 8}\hfill \\ \text{O= 1×4= 4 O= 4 }\hfill \end{array}$

So, finally the given equation is balanced

${\text{PCl}}_{\text{5}}{\text{+ 4H}}_{\text{2}}{\text{O = H}}_{\text{3}}{\text{PO}}_{\text{4}}\text{+ 5HCl}$

Conclusion

The balanced equation is

${\text{PCl}}_{\text{5}}{\text{+ 4H}}_{\text{2}}{\text{O = H}}_{\text{3}}{\text{PO}}_{\text{4}}\text{+ 5HCl}$