Chapter U6.120, Problem 1TAI

Interpretation Introduction

Interpretation: The way to predict if products are favored in a reversible reaction needs to be explained.

Concept introduction: The chemical reaction is represented in the form of an equation in which reactants are written on the left hand side and products on right hand side. The reactants and products are separated by placing an arrow between them.

Explanation of Solution

The normal chemical equation is represented as follows:

  $A+B\to AB$

The above reaction shows that A and B react to form AB.

When a double arrow is placed between reactant and product, the chemical equation is represented as follows:

  $A+B\rightleftarrows AB$

According to above chemical equation, A and B react to form AB and AB can further dissociate to form A and B.

Thus, the reaction is reversible in nature. Here, double arrow shows that reaction can go in both the directions or it is reversible in nature.

Whether the reactant or product is favored can be determine from the length of the arrow. If the length of the arrow is in forward direction more than that of the backward direction, product is favored. If the length of the arrow in the backward direction is more then the reactant is favored.

Thus, if the length of the arrow is more in the forward direction in a reversible reaction, product will be favored. This is represented as follows:

  $A+B⥂AB$

Here, the above reaction has double arrow thus, it is reversible in nature but more towards product side.

This can also be verified by calculating the K_c value. For the above reaction, K_c is represented as follows:

  $K_c=\frac{\left[AB\right]}{\left[A\right]\left[B\right]}$

If the value of K is more than 1 thus, product is favored and if the value is less than 1, reactants will be favored.