1. Tardigrade
  2. Question
  3. Chemistry
  4. For an exothermic reaction, following two steps are involved. <img class=img-fluid question-image alt=image src=https://cdn.tardigrade.in/img/question/chemistry/3e7fb217ac68cb9cce9d6b53ed7dd9de-.png /> Which of the following graphs correctly represent this reaction ?

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Q. For an exothermic reaction, following two steps are involved.

image

Which of the following graphs correctly represent this reaction ?

NTA AbhyasNTA Abhyas 2020Chemical Kinetics

Solution:

In any reaction mechanism the no. of activated complexes showing maxima of potential energies is the no. of steps in that mechanism and in between these maxima is a valley where lies a more stable intermediate. There is one reaction intermediate lying at valley of two maxima representing two steps. $E_{a}$ for first step should be higher than second step as first is slow step. These requirements fulfilled by choice (ii) & not choice (i) the choice (iv) is not possible because that is for endothermic reaction $(\Delta H + ve ) \&$ (ii) is single step equation so not possible.