Chapter 15.7, Problem 1PPC

Interpretation Introduction

Interpretation:

Whether the reaction will proceed to the right, the left, or neither to achieve equilibrium for each of the given diagrams is to be determined.

Concept introduction:

Chemical equilibrium is a state of the chemical reaction when the rate of forward reaction becomes equal to the rate of reverse reaction and the concentration of the products and reactants becomes constant known as equilibrium concentrations.

For a general reaction: $a\text{A}\text{+}b\text{B}\rightleftarrows c\text{C}\text{+}d\text{D}$.

Reaction quotient is defined as the ratio of concentration of products and reactants of chemical species present in the reaction mixture at a given point of time. It is denoted with $\text{Q}$.

$\text{Reaction quotient, }{Q}_c=\frac{{\left[\text{C}\right]}^{\text{c}}{\left[\text{D}\right]}^{\text{d}}}{{\left[\text{A}\right]}^{\text{a}}{\left[\text{B}\right]}^{\text{b}}}$.

Equilibrium constant is defined as the ratio of concentration of products and the concentration of reactants, which are in equilibrium, and its value is constant at a particular temperature. It denoted by K.

$\text{Equilibrium constant, }{K}_c=\frac{{\left[\text{C}\right]}^{\text{c}}{}_{\text{eqm}}{\left[\text{D}\right]}^{\text{d}}{}_{\text{eqm}}}{{\left[\text{A}\right]}^{\text{a}}{}_{\text{eqm}}{\left[\text{B}\right]}^{\text{b}}{}_{\text{eqm}}}$

Here, $K_C$ is the equilibrium constant and $C$ in $K_C$ stands for the concentration. $\left[\text{A}\right]$, $\left[\text{B}\right]$, $\left[\text{C}\right]$, and $\left[\text{D}\right]$ are the equilibrium concentration of reactants A and B and product C and D, respectively.

A and B are reactants, C and D are products, and $a,b,c$, and $d$ are their respective stoichiometric coefficients.

At equilibrium, $Q_c=K_c$

The equilibrium concentration of reactants and products, present in liquid or solid phase, in the reaction is considered to be $1$ in the expression of equilibrium constant.