Chapter 17, Problem 2STP

Interpretation Introduction

Interpretation: True statement is to be given.

Concept Introduction: At equilibrium, rate of forward reaction is equal to the rate of the backward reaction. In other words, the rate at which the reactants are formed is equal to the rate at which products are formed.

Answer to Problem 2STP

Correct answer: The concentration of reactant(s) is constant over time.

Explanation of Solution

Reason for correct option: At equilibrium, the rate at which the reactants are formed is equal to the rate at which products are formed. Thus, the concentrations of reactants and products remain practically constant as long as the system is in equilibrium.

Conclusion

Reasons for incorrect options:

1. At equilibrium, the rate of forward is equal to rate of the backward reactions. This does not imply that the concentrations of reactants and products are equal.
2. At equilibrium, reactants and products both are getting formed as a result of backward and forward reaction.
3. The rate of forward as well as rate of the backward reaction are equal but not equal to zero. If that happens, there would be no reaction taking place at equilibrium but in actual reaction does take place.