Answer:
0.328 mol/dm³
Explanation:
We have
I started this calculation from Rate's law.
Remember equilibrium constant has been given to be 60%
Our interest is Kc, that is the equilibrium constant.
Ca = 4(1-0.6)/1+(-0.5*0.6)
= 4-2.4/1-0.3
= 1.6/0.7
= 2.2857
Cb = 4x0.6/2(1+(-0.5*0.6))
= 2.4/2(0.7)
= 2.4/1.4
= 1.7143
Kc = Cb/Ca²
= 1.7143/2.2857²
= 1.7143/5.2244
= 0.328 mol/dm³
I have added an attachment showing earlier stages to the final answer