Question

For the reaction\[A \to B + C\], the energy profile diagram is given in the figure.
The decrease in the energy of activation in the presence of catalyst is given by:

\[
  {A:{\text{ }}Z} \\
  {B:{\text{ }}Z - P} \\
  {C:{\text{ }}Y - Z} \\
  {D:{\text{ }}Z - X}
\]

Answer 1

Hint:The activation energy is referred to as the minimum energy that is required for a chemical reaction to take place. If a reaction is having a low activation energy then that means the reaction will proceed fast because many particles will possess the required energy.

Complete answer:
A Catalyst is basically a substance which is supposed to accelerate the rate of any chemical reaction without requiring to undergo any change in the chemical composition or mass during the chemical reaction. A catalyst accelerates the rate of a chemical reaction by lowering down the activation energy.
It is clearly visible in the figure that in the absence of a catalyst, ‘Z’ is the activation energy while in the presence of the catalyst, ‘P’ is the activation energy. And you can easily observe that \[Z{\text{ }} > {\text{ }}P\]. So, the
So, the decrease in the energy of activation in the presence of a catalyst is given by \[Z - P\].

Hence, the correct answer is Option B.

Note:
Always remember that the activation energy in a reaction is always positive. We know that the energy changes which result from a chemical reaction can either be positive, negative, or even zero, but it is also true that in all of the cases, an energy barrier has to be overcome before any reaction takes place. It should be noted that higher the activation energy, slower will be the chemical reaction.