Answer: The equilibrium concentration of
, expressed in scientific notation is 
Explanation:
Equilibrium constant is the ratio of the concentration of products to the concentration of reactants each term raised to its stochiometric coefficients.
The given balanced equilibrium reaction is,

At eqm. conc. (0.30) M (0.10) M (x) M (0.020) M
The expression for equilibrium constant for this reaction will be,
![K_c=\frac{[CH_4]\times [H_2O]}{[CO]\times [H_2]^3}](https://tex.z-dn.net/?f=K_c%3D%5Cfrac%7B%5BCH_4%5D%5Ctimes%20%5BH_2O%5D%7D%7B%5BCO%5D%5Ctimes%20%5BH_2%5D%5E3%7D)
Now put all the given values in this expression, we get :

By solving the term 'x', we get :
x = 0.059 M= 
Thus, the concentrations of
at equilibrium is :
Concentration of
= (x) M = 
The equilibrium concentration of
, expressed in scientific notation is 