Question

The system described by the reaction CO(g)+Cl2(g)⇌COCl2(g) is at equilibrium at a given temperature when PCO= 0.26 atm , PCl2= 0.15 atm , and PCOCl2= 0.66 atm . An additional pressure of Cl2(g)= 0.39 atm is added. Find the pressure of CO when the system returns to equilibrium.

Answer 1

Answer: The new pressure of CO is 0.09 atm

Explanation:

For the given chemical reaction:

$CO(g)+Cl_2(g)\rightleftharpoons COCl_2(g)$

The expression of $K_p$ for above equation follows:

$K_p=\frac{p_{COCl_2}}{p_{CO}\times p_{Cl_2}}$             .......(1)

We are given:

$p_{COCl_2}=0.66atm\\p_{CO}=0.26atm\\p_{Cl_2}=0.15atm$

Putting values in above equation, we get:

$K_p=\frac{0.66}{0.15\times 0.26}\\\\K_p=16.92$

Addition pressure of chlorine added = 0.39 atm

Now, the equilibrium is re-established:

                    $CO(g)+Cl_2(g)\rightleftharpoons COCl_2(g)$

Initial:            0.26     0.15             0.66

At eqllm:     0.26-x   0.54            0.66+x

Putting values in expression 1, we get:

$16.92=\frac{(0.66+x)}{(0.26-x)\times 0.54}\\\\x=0.17$

So, new pressure of CO = 0.26 - x = (0.26 - 0.17) = 0.09 atm

Hence, the new pressure of CO is 0.09 atm