At 35°C, Kc = 1.6 multiplied by10-5 for the following reaction
2 NOCl(g) reverse reaction arrow 2 NO(g)+ Cl2(g)

Calculate the concentrations of all species at equilibrium if

2.0 mol NO and 1.0 mol of Cl2 are placed in a 1.0 L flask

Respuesta :

Answer : The equilibrium concentrations of all species [tex]NO,Cl_2\text{ and }NOCl[/tex] are, 0.05 M, 0.043 M and 0.975 M respectively.

Explanation : Given,

Moles of  [tex]NO[/tex] = 2 mole

Moles of  [tex]Cl_2[/tex] = 1 mole

Volume of solution = 1 L

Initial concentration of [tex]NO[/tex] = 2 M

Initial concentration of [tex]Cl_2[/tex] = 1 M

The given balanced equilibrium reaction is,

                            [tex]2NO(g)+Cl_2(g)\rightleftharpoons 2NOCl(g)[/tex]

Initial conc.          2 M            1 M            0

At eqm. conc.    (2-2x) M   (1-x) M         (2x) M

The expression for equilibrium constant for this reaction will be,

[tex]K_c=\frac{[NOCl]^2}{[NO]^2[Cl_2]}[/tex]

The [tex]K_c[/tex] for reverse reaction = [tex]\frac{1}{1.6\times 10^{-5}}[/tex]

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

[tex]\frac{1}{1.6\times 10^{-5}}=\frac{(2x)^2}{(2-2x)^2\times (1-x)}[/tex]

By solving the term 'x', we get :

x = 0.975

Thus, the concentrations of [tex]NO,Cl_2\text{ and }NOCl[/tex] at equilibrium are :

Concentration of [tex]NO[/tex] = (2-2x) M  = (2 - 2 × 0.975) M = 0.05 M

Concentration of [tex]Cl_2[/tex] = (1-x) M = 1 - 0.975 = 0.043 M

Concentration of [tex]NOCl[/tex] = x M = 0.975 M

Therefore, the equilibrium concentrations of all species [tex]NO,Cl_2\text{ and }NOCl[/tex] are, 0.05 M, 0.043 M and 0.975 M respectively.