Question

Please explain step by step.

The equilibrium constant K for the reaction 2 H2O2(g) 2 H2O(g) + O2(g) is 3.9 x 10-3 at 300oC. A mixture contains the gases at the following concentrations: [H2O2] = 5.0 x 10-3 mol/L, [H2O]=2.5 x 10-3 mol/L, [O2]= 2.0 x 10-3 mol/L. (i) Is the reaction at equilibrium at 300oC? Explain your answer. If not, in what direction does the reaction proceed to come into equilibrium? Describe what happens over time to the rate of both the forward and reverse reactions.

Answer 1

From the following calculation, it can be easily understood that the reaction is not in equilibrium. To come to the equilibrium, the concentration of H2O2 must be decreased and the concentration of H2O and O2 must be increased i.e the reaction need to proceed in the forward direction. With time as the reaction proceeds towards equilibrium, the rate of the forward reaction will decrease and that of the reverse or backward reaction will increase. At equilibrium, this two rates will be equal.The calculation is given below.