Chapter 20, Problem 88A

Interpretation Introduction

Interpretation:

The possibility of two molecules colliding but not reacting is to be explained.

Concept introduction:

For two molecules to react, the molecules must collide with sufficient amount of activation energy.

Answer to Problem 88A

Two molecules can collide but still not react if there is not sufficient activation energy or the orientation of colliding molecules does not favor the reaction.

Explanation of Solution

The presence of sufficient activation energy is necessary for the reaction to happen. Even if there is sufficient energy, the orientation of molecules must be such that it favors the formation and cleavage of bonds necessary for the reaction. The motion of molecules in fluid medium is random which can either allow or reject reaction even after collisions.

Conclusion

The probability of two molecules colliding and reacting depends on their activation energy and orientation.