Chapter U6, Problem SII4RE

(a)

Interpretation Introduction

Interpretation: The equilibrium-constant equation for the given reaction needs to be determined.

  ${\text{2NO}}_{\text{(g) }}{\text{+ Br}}_{\text{2(g)}}\rightleftharpoons {\text{2NOBr}}_{\text{(g)}}$

Concept Introduction: The reversible reaction can proceed in either directions; forward and backward direction.

The rate of forward and backward reactions become equal to each other therefore as reactant forms product, the product converts to reactant.

The equilibrium stage is the stage of reversible reaction at which the rate of forward becomes equal to rate of backward reaction.

Answer to Problem SII4RE

  $\begin{array}{l}{\text{2 NO}}_{\text{(g) }}{\text{+ Br}}_{\text{2(g)}}\rightleftharpoons {\text{2NOBr}}_{\text{(g)}}\\ {\text{K}}_{\text{eq}}\text{= }\frac{{{\text{[NOBr}}_{\text{(g)}}\text{]}}^{\text{2}}}{{{\text{[NO}}_{\text{(g) }}]}^2[{\text{Br}}_{\text{2(g)}}]}\end{array}$

Explanation of Solution

The equilibrium reaction is represented as follow:

  ${\text{2NO}}_{\text{(g) }}{\text{+ Br}}_{\text{2(g)}}\rightleftharpoons {\text{2NOBr}}_{\text{(g)}}$

The equilibrium constant represents the ratio of equilibrium concentrations of product and reactant. Thus the equilibrium constant expression for the given reaction must be written as:

  $\begin{array}{l}{\text{2 NO}}_{\text{(g) }}{\text{+ Br}}_{\text{2(g)}}\rightleftharpoons {\text{2NOBr}}_{\text{(g)}}\\ {\text{K}}_{\text{eq}}\text{= }\frac{{{\text{[NOBr}}_{\text{(g)}}\text{]}}^{\text{2}}}{{{\text{[NO}}_{\text{(g) }}]}^2[{\text{Br}}_{\text{2(g)}}]}\end{array}$

(b)

Interpretation Introduction

Interpretation: The change during the addition of ${\text{NOBr}}_{\text{(g)}}$ on equilibrium for the given reaction needs to be explained.

  ${\text{2NO}}_{\text{(g) }}{\text{+ Br}}_{\text{2(g)}}\rightleftharpoons {\text{2 NOBr}}_{\text{(g)}}$

Concept Introduction: The reversible reaction can proceed in either directions; forward and backward direction.

The rate of forward and backward reactions become equal to each other therefore as reactant forms product, the product converts to reactant.

The equilibrium stage is the stage of reversible reaction at which the rate of forward becomes equal to rate of backward reaction.

Answer to Problem SII4RE

Addition of ${\text{NOBr}}_{\text{(g)}}$ increases the concentration of product so reaction will shift to backward direction towards reactant.

Explanation of Solution

The Le Chatelier's principle states that effect of change in reaction condition shifts the reaction equilibrium in that direction which can minimize the effect of change. Addition of ${\text{NOBr}}_{\text{(g)}}$ , increases the concentration of product so reaction will shift to backward direction towards reactant.

(c)

Interpretation Introduction

Interpretation: The direction in which the reaction shifts if the pressure inside the container will increase needs to be determined.

  ${\text{2NO}}_{\text{(g) }}{\text{+ Br}}_{\text{2(g)}}\rightleftharpoons {\text{2 NOBr}}_{\text{(g)}}$

Concept Introduction: The reversible reaction can proceed in either directions; forward and backward direction.

The rate of forward and backward reactions become equal to each other therefore as reactant forms product, the product converts to reactant.

The equilibrium stage is the stage of reversible reaction at which the rate of forward becomes equal to rate of backward reaction.

Answer to Problem SII4RE

If the pressure inside the container will increase, the reaction will move towards forward direction.

Explanation of Solution

The Le Chatelier's principle states that effect of change in reaction condition shifts the reaction equilibrium in that direction which can minimize the effect of change.

If the pressure of container increases, the reaction will move towards product (forward reaction). This is because increase in pressure will move reaction to decrease the pressure towards forward direction to make lesser gaseous molecules.

(d)

Interpretation Introduction

Interpretation: The direction in which the reaction shifts if the volume of the container will increase needs to be determined.

  ${\text{2NO}}_{\text{(g) }}{\text{+ Br}}_{\text{2(g)}}\rightleftharpoons {\text{2 NOBr}}_{\text{(g)}}$

Concept Introduction: The reversible reaction can proceed in either directions; forward and backward direction.

The rate of forward and backward reactions become equal to each other therefore as reactant forms product, the product converts to reactant.

The equilibrium stage is the stage of reversible reaction at which the rate of forward becomes equal to rate of backward reaction.

Explanation of Solution

The Le Chatelier's principle states that effect of change in reaction condition shifts the reaction equilibrium in that direction which can minimize the effect of change.

If the volume of container increases, the reaction will move towards product (forward reaction). This is because increase in volume will move reaction to decrease the volume towards forward direction to make lesser gaseous molecules.