Chapter 17, Problem 12A

Interpretation Introduction

Interpretation: Defining the chemical reversible reaction. Examining the question whether all chemical reaction are reversible or not. Examining the question whether some reaction more likely to occur in one direction or not.

Concept introduction:A reversible chemical reaction can be defined as a reaction that can go in both forward and backward directions. The reactants can change into the products, and the products can change back into the reactants.This keeps on happening until it reaches equilibrium.

Equilibrium constant $K$ is defined as a ratio of the concentration of products to the concentration of the reactants.

The expression for equilibrium constant $K$

  $=\frac{\text{concentration of the products}}{\text{concentration of the reactants}}$

  $K$ gives the extent of the progress of the reaction.

Answer to Problem 12A

In principle all chemical reactions are reversible.

Yes, some reactions are more likely to occur in one direction.

Explanation of Solution

All chemical reactions are reversible, at least in principle. Equilibrium is dynamic in nature; it may appear that no change is happening. But actually, both forward and backward reaction occurs at same rate. Reactants get combined to form the products and the products combe to form the reactants.

Some chemical reactions are likely to occur in one direction. These reactions are called irreversible reactions.Irreversible reactions are marked by their high value of equilibrium constant $K.$ High value of $K$ indicates that concentration of products is greater than the concentration of the reactants. That means that the reaction is more favorable in forward direction.

In a complete combustion reaction, fuel (generally hydrocarbons) and oxygen reacts to form carbon dioxide and water. These two products cannot react to regenerate the fuel and oxygen, so the reaction is irreversible.

Conclusion

In principle, all chemical reactions are reversible.

Yes, some reactions are more likely to occur in one direction.