At a certain temperature, the reaction 2NO + Cl2 ⇌ 2NOCl has an equilibrium constant Kc of 45.0. A chemist creates a mixture with the following initial concentrations: [NO] = 0.10 M, [Cl2] = 0.20 M, and [NOCl] = 0.30 M. What will happen as the reaction begins?

This is an incomplete question, here is a complete question.

At a certain temperature, the reaction  has an equilibrium constant Kc of 45.0. A chemist creates a mixture with the following initial concentrations: [NO] = 0.10 M, [Cl₂] = 0.20 M, and [NOCl] = 0.30 M. What will happen as the reaction begins?

A. [NOCl] will increase.

B. [NOCl] will decrease.

C. [NOCl] will stay the same.

D. There is not enough information to answer the question.

Answer : The correct option is, (C) [NOCl] will stay the same.

Explanation :

Reaction quotient (Q) : It is defined as the measurement of the relative amounts of products and reactants present during a reaction at a particular time.

The given balanced chemical reaction is,

The expression for reaction quotient will be :

In this expression, only gaseous or aqueous states are includes and pure liquid or solid states are omitted.

Now put all the given values in this expression, we get

The given equilibrium constant value is,

Equilibrium constant : It is defined as the equilibrium constant. It is defined as the ratio of concentration of products to the concentration of reactants.

There are 3 conditions:

When that means product > reactant. So, the reaction is reactant favored.

When that means reactant > product. So, the reaction is product favored.

When that means product = reactant. So, the reaction is in equilibrium.

From the above we conclude that, the that means product = reactant. So, the reaction is in equilibrium that means the concentration of NOCl will stay the same.

Hence, the correct option is, (C) [NOCl] will stay the same.