How can I find the equilibrium constant of a reversed reaction?

Hint: When a chemical reaction is started between the reactants it reaches a stage where it reaches a constant and it is called equilibrium constant. The chemical equilibrium constant can be expressed with a symbol ${{K}_{eq}}$ .

Complete answer:
- In the question it is asked how we can find the equilibrium constant of a reversed reaction.
- To determine the equilibrium constant of a reaction we have to consider a reversible reaction.
- Consider a reversible reaction and the chemical reaction is as follows.
\[A+B\rightleftharpoons C+D\]
- In the above chemical reactions A and B are the reactants and C and D are the products.
- The reactants and the products are in equilibrium in the above chemical reaction.
- The equilibrium constant for the above mentioned chemical reaction is as follows.
\[{{K}_{eq}}=\dfrac{[C][D]}{[A]][B]}\]
- Means the equilibrium constant is nothing but the ratio of concentration of the products to the concentration of the reactants.
- The above mentioned equilibrium constant is for the forward reaction and we write the chemical equilibrium constant for the reverse reaction and it is as follows.
\[{{K}_{eq}}=\dfrac{[A][B]}{[C]][D]}\]
 - This is how we can find the chemical equilibrium constant for a reversible chemical equation.

Note:
The equilibrium constant of a chemical reaction is going to play a big role to find the status of the chemical reaction means whether the chemical reaction has reached the equilibrium or not. Once the chemical reaction reaches equilibrium the concentration of the reactants will be equal to the concentration of the products.