Chapter 17, Problem 17.91P

Interpretation Introduction

Interpretation:

The conversion of acetylene to ethylene is given as

  ${\text{C}}_{\text{2}}{\text{H}}_{\text{2(g)}}{\text{+ H}}_{\text{2(g)}}\rightleftharpoons {\text{C}}_{\text{2}}{\text{H}}_{\text{4(g)}}$

The calculated ${\text{K}}_{\text{c}}\text{ at 2000}\text{.K is 2}{\text{.9×10}}^{\text{8}}$.  But the process is run at lower temperatures with the aid of a catalyst to prevent decomposition.  By using ${\text{ΔH}}^{\text{°}}$ values, ${\text{K}}_{\text{c}}$ has to be calculated at $\text{300}\text{.K}$.

Concept Introduction:

Equilibrium constant:

The relationship between the concentration of products and concentration of reactants in a chemical reaction at equilibrium is said to be equilibrium constant.  It is denoted by $\text{K}$.

For a reaction,

  $\text{xX + yY }\rightleftharpoons \text{ zZ}$

The expression of $\text{K}$ can be given as

  $\begin{array}{l}{\text{K}}_{\text{c}}\text{ = }\frac{{\text{[Z]}}^{\text{z}}}{{\text{[X]}}^{\text{x}}{\text{[Y]}}^{\text{y}}}\\ \\ \text{where,}\text{[X] = equilibrium concentration of X}\\ \\ \text{[Y] = equilibrium concentration of Y}\\ \\ \text{[Z] = equilibrium concentration of Z}\end{array}$