Question

Question: Is it true that the value of K depends on the amounts of reactants and/or products that are mixed together initially? Explain. Is it true that reactions with large equilibrium constants are very fast? Explain.

Short answer

Answer

It is not true that the value of K depends on the amounts of reactants or products that are mixed together initially. The value of K depends on the temperature only but not the initial conditions of the equilibrium reaction.

It is not true that reactions with large equilibrium constants are very fast because the activation energy defines the speed of reactions. Both the rate of the reaction and the equilibrium constant are not related to each other.

Step-by-step solution

Equilibrium constant

It is not true that the value of K depends on the amounts of reactants or products that are mixed together initially. The value of K depends on the temperature only but not the initial conditions of the equilibrium reaction.

Consider an equilibrium reaction that has three different initial conditions.

Case I:

In this case, the experiment was conducted by placing reactants only under initial conditions.

Case II:

In this case, the experiment was conducted by introducing some reactants and products under initial conditions.

Case III:

In this case, the experiment was conducted by placing products only at initial conditions.

The equilibrium constant value for three different cases has the same because it is independent of initial conditions.

Are reactions with large equilibrium constant fast

It is not true that reactions with large equilibrium constants are very fast because the activation energy defines the speed of reactions. Both the rate of the reaction and the equilibrium constant are not related to each other.

A fast reaction may or may not have a larger equilibrium constant. It is true for a slow reaction.