Consider the following system at equilibrium where Delta H degree = 87.9 kj. and
ID: 872408 • Letter: C
Question
Consider the following system at equilibrium where Delta H degree = 87.9 kj. and Kc = 1.20E-2. at 500 K PCl5(g) PCL3(g)+CL2(g) If the TEMPERATURE on the equilibrium system is suddenly decreased: The value of Kc: Increases Decreases Remains the same The value of Qc: Is greater than Kc Is equal to Kc Is less than Kc The reaction must: Run in the forward direction to restablish equilibrium. Run in the reverse direction to restablish equilibrium. Remain the same. Already at equilibrium. The concentration of H2 will: Increase Decrease. Remain the same.Explanation / Answer
Temperature is directly proportional to equilibrium constant KC , which means that with decrease in temperature KC will decrease. Hence, the correct option is B, that the value of KC will decrease.
Since the value of KC is 1.20 x 10-2 that is, KC < 1, it means that the concentration of reactant is greater than that of products. Therefore, the reaction proceeds in backward direction. When KC < QC , then the reaction favors backward direction. Hence, thecorrect option is A.
Since, with decrease in temperature the KC decreases hence, the reaction will occur in reverse direction to reestablish equilibrium. Hence, the correct option is B.
Since, the reaction occurs in reverse direction therefore, the amount of Cl2 present will be converted back into the reactant which results decease in the concentration of Cl2 . Hence, the correct option is B.