Chapter 17.5, Problem 17.6BFP

Interpretation Introduction

Interpretation:

For the reaction of formation of sulfur trioxide, whether the given reaction condition is at equilibrium or not has to be determined. If not, the direction to which the reaction will proceed has to be given.

Concept Introduction:

Reaction Quotient:

Reaction quotient, Q is the ratio between product of the product concentration to the product of the reactant concentration with each term raised to the power of its balancing coefficient.

Consider a general equation,

  $a\text{A +}b\text{A}\stackrel{}{\rightleftharpoons }c\text{C}+d\text{D}$

Where a, b, c and d are the stoichiometric coefficients.  The reaction quotient is,

  ${\text{Q}}_{\text{c}}\text{ = }\frac{{\text{[C]}}^{\text{c}}{\text{[D]}}^{\text{d}}}{{[\text{A]}}^{\text{a}}{\text{[B]}}^{\text{b}}}$

Comparison of ${\text{Q}}_{\text{c}}{\text{ and K}}_{\text{c}}$ :

When ${\text{Q}}_{\text{c}}{\text{ < K}}_{\text{c}}$, the reaction will proceed in right direction, $\text{reactants}\stackrel{}{\to }\text{products}$

When ${\text{Q}}_{\text{c}}{\text{ > K}}_{\text{c}}$, the reaction will proceed in left direction, $\text{reactants}\stackrel{}{\leftarrow }\text{products}$

When ${\text{Q}}_{\text{c}}{\text{ = K}}_{\text{c}}$, the reaction will remain unchanged, $\text{reactants}\stackrel{}{\rightleftharpoons }\text{products}$