Short Answer 
The reaction involves the decomposition of COCl‚ÄöCC into CO‚ÄöCC and Cl‚ÄöCC, with initial conditions of 1 atm pressure and 690 K. The change in pressure was calculated, leading to equilibrium pressures and finally, the equilibrium constant Kp was determined to be 0.05 at the given temperature.
Step 1: Understand the Reaction and Initial Conditions
The decomposition of COCl‚ÄöCC(g) into CO‚ÄöCC(g) and Cl‚ÄöCC(g) is described by the equation: COCl‚ÄöCC(g) ‚ÄöUi CO‚ÄöCC(g) + Cl‚ÄöCC(g). At the start, the total pressure in the flask is given as 1 atm under a temperature of 690 K. As the reaction progresses, the final pressure measured is 1.2 atm.
Step 2: Calculate the Change in Pressure
To find the change in pressure due to the decomposition of the reactant, we can denote the pressure of the products (CO‚ÄöCC and Cl‚ÄöCC) produced as x. The equilibrium pressure equation can be set up as follows: (1 – x) + x + x = 1.2. Solving this gives us:
- x = 0.2 atm (pressure of both products)
- Resulting equilibrium pressures: pCO‚ÄöCC = 0.2 atm, pCl‚ÄöCC = 0.2 atm, and pCOCl‚ÄöCC = 0.8 atm.
Step 3: Calculate the Value of Kp
Kp is determined using the equilibrium pressures of the components in the reaction. The formula for Kp is expressed as: Kp = (pCO‚ÄöCC * pCl‚ÄöCC) / pCOCl‚ÄöCC. Plugging in the values we found earlier:
- Kp = (0.2 * 0.2) / 0.8
- Kp = 0.04 / 0.8 = 0.05
Thus, the calculated value of Kp for the reaction at 690 K is 0.05.