
Answer:
pCOFâ‚‚ = 101.8 kPa = 1.018 bar
Explanation:
What we need is to determine the equilibrium pressure for COFâ‚‚ .
Now the equilibrum is
              2COF2(g)⇌  CO2(g)+  CF4(g)  with Kp = 7.80
initially kPa      240         0        0
react            -2x         + x       + x
equilibrium     240-2x        +x       +x
Kp = pCOâ‚‚ x pCFâ‚„ / p COFâ‚‚
7.80 = x² /( 240-2x )²
taking square roots to both sides of the equation
√7.80 = √(x² /( 240-2x )²)
2.8 = x / ( 240 - 2x )
672 - 5.6x = x
672 = 6.6x
672//6.6 = x = 101.8
pCOFâ‚‚ = 101.8 kPa = 1.018 bar