Question

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R:
Assertion A: A reaction can have zero activation energy.
Reasons R: The minimum extra amount of energy absorbed by reactant molecules so that their energy becomes equal to threshold value, is called activation energy.
In the light of the above statements, choose the correct answer from the options given below:

• A. Both A and R are true and R is NOT the correct explanation of A
• B. A is true but R is false
• C. A is false but R is true
• D. Both A and R are true and R is the correct explanation of A

Answer 1

The Correct Option is C

To address this question, we must analyze both the assertion and the reason provided:

• Assertion A: A reaction can have zero activation energy.
  The assertion states that there can be reactions with zero activation energy. This means that such reactions would proceed without the need for an energy boost to overcome any energy barrier.
• Reason R: The minimum extra amount of energy absorbed by reactant molecules so that their energy becomes equal to threshold value, is called activation energy.
  The reason explains that activation energy is the additional energy needed by reactants to reach the threshold energy required for the reaction to proceed.

Now, let's evaluate the statements:

1. The assertion that a reaction can have zero activation energy is generally false. Most chemical reactions involve overcoming an energy barrier, meaning they usually require non-zero activation energy. Only in rare cases, such as certain elementary reactions and those involving resonance stabilization, might this be considered true.
2. The reason correctly defines activation energy. It is indeed the energy required for reactants to reach a state where they can transform into products. Thus, Reason R is true.

Based on the above evaluation:

• The correct answer is that A is false but R is true.

This determination is based on the understanding that in most typical scenarios, reactions require some amount of activation energy, aligning with Reason R's accurate definition of activation energy.