Chapter 16.4, Problem 37SSC

Interpretation Introduction

Interpretation:

The difference between an intermediate and an activated complex needs to be explained.

Concept introduction:

Chemical kinetic is the branch of chemistry that deals with kinetic or rate of a chemical reaction. The rate of reaction can be defined as the change in the concentration of reactant and product with time. The rate of reaction mainly depends on the activation energy. The minimum energy that is required for the conversion reactant to product is called as activation energy.

Answer to Problem 37SSC

Activated complex	Intermediate
Highly unstable	Less unstable than activated complex
Cannot isolate	Can isolate
Very high energy	High energy than reactant and product
Example: Activated complex	Example: Carbocation, carbanion, carbene

Explanation of Solution

The reaction sequence of a multi-step reaction which defines the complete conversion reactant to product molecules is called as reaction mechanism. The active species which are formed during reaction mechanism and are readily converted to product are called as intermediate. Once the reactant molecules acquire activation energy, they form activated complex which is highly unstable due to highest energy and readily converts to product.

Thus the major difference between activated complex and intermediate is:

Activated complex	Intermediate
Highly unstable	Less unstable than activated complex
Cannot isolate	Can isolate
Very high energy	High energy than reactant and product
Example: Activated complex	Example: Carbocation, carbanion, carbene

Conclusion

Activated complex are unstable species whereas intermediates are more stable than activated complex.