Chapter 18, Problem 89A

Interpretation Introduction

Interpretation: The effect on equilibrium position if the volume decreases is to be explained.

Concept introduction: Volume is inversely proportional to pressure. Therefore, if the volume drops, the pressure will increase.

Answer to Problem 89A

Decreasing the volume will cause the equilibrium to move toward the forward reaction.

Explanation of Solution

The given reaction is as follows:

  $\text{4HCl}\left(g\right)+{\text{O}}_2\left(g\right)\rightleftharpoons 2{\text{Cl}}_2\left(g\right)+2{\text{H}}_{\text{2}}\text{O}\left(g\right)$

In the given reaction, $4$ moles of $\text{HCl}$ gas react with $1$ moles of ${\text{O}}_2$ gas to produce $2$ moles of ${\text{Cl}}_2$ gas and $2$ moles of ${\text{H}}_{\text{2}}\text{O}$ vapor. The left side contains five gaseous molecules, and the right contains four.

The equilibrium moves in the direction of producing fewer molecules as the pressure of the gas mixture increases. Pressure and volume are inversely proportional to one other. Therefore, decreasing the volume will shift the equilibrium in the forward direction.

Conclusion

Decreasing the volume will cause the equilibrium to move toward the forward reaction.