In: Chemistry
K for the given reaction can be written as,
K = [CO2][CF4]/[COF2]^2
ICE table
2COF2 <=====> CO2 + CF4
Initial 2.00M 0 0
change 2x x x
equilibrium (2-2x) x x
Feed the values,
8.60 = x^2/(2-2x)^2
Solve for x,
x = 0.85434 M
So, the equilibrium concentration of COF2 = 2.00 - 2 x 0.85434 = 0.29132 M (or 0.30 M)