CSTR operates in steady state and the temperature is constant to carry out the liquid phase reversible reaction A to B. The feed contains a component whose concentration is , and the concentration of A there is 50 mol/lit. A residence time is required in the reactor for the conversion 10 s and 20s, the concentrations of A at the reactor exit are 30 mol/lit and 1mol/lit, respectively. Suppose that the first order rate law applies to the forward and backward reactions. Assume as well that the molar density of the system is constant. Get the forward reaction's rate constant (in s1).