Chapter 16, Problem 1RQ

Interpretation Introduction

Interpretation:

Rate of forward and reverse reaction at equilibrium has to be determined.

Concept Introduction:

Rate of reaction is variable and depends on concentration of species reacted, temperature, pressure, catalyst, and nature of reactant.

Explanation of Solution

For reversible reaction, rate of forward and reverse reaction become equal at some point in time. Forward reaction rate decrease as a result of decreased amounts of reactant, and after sometime when products formed. Then reverse reaction starts. When forward reaction rate and reverse reaction rate become equal, state of chemical equilibrium has been reached. An equilibrium represents a dynamic state in which two opposed processes take place at same time and same rate.

For equilibrium reaction rate of forward reaction is equal to rate of reverse direction. Consider a general reaction that is as follows:

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

Expression for equilibrium constant is written as follows:

  $K_{\text{eq}}=\frac{{\left[\text{C}\right]}^c{\left[\text{D}\right]}^d}{{\left[\text{A}\right]}^a{\left[\text{B}\right]}^b}$

Here,

$K_{\text{eq}}$ is equilibrium constant.

$\left[\text{A}\right]$, $\left[\text{B}\right]$, $\left[\text{C}\right]$ and $\left[\text{D}\right]$ are concentration of substances in reaction.

$a$, $b$, $c$ and $d$ are coefficients of substances.