Question

The rate constant for phosgene formation from CO and Cl2 in the gas phase at 150*C was found to be 1.29x10^-2 L*mol^-1*s^-1. If an experiment was begun in a container with a fixed volume and the partial pressures of both CO and Cl2 were 2.5 bar, how long (in s) would it take for the total pressure in the container to decrease to 4.0 bar? (don't forget to convert pressure to concentration units)

Answer 1

CO + CL₂ -> COCL₂   K = 1.29 * 10-2 L mol^-1 s^-1

P_i= 2.5 + 2.5 (5)    0 from unit of of k reaction is of 2^nd order

P_t= (4)

to converet pressure into units of concerntration we apply ideal gas law

N/V =P/RT

C =4 BAR / 0.0831 *423 =  0.1137MOLE / L

C_{0 =} 5 BAR / 0.0831 *423 = 0.1422 MOLE / L

RATE = k [co] [cl₂]^3/2

t=1/k (1/[a] - 1/[a⁰])

= 1/1.29 * 10-2 ( 1/0.1137 - 1/ 0.1422 )

= 0.7751  * 10-2 (8.7950 - 7.0323)

=0.1366 * 10-2 SEC