Question

Carbonyl fluoride, COF2, is an important intermediate used in the production of fluorine-containing compounds. For instance, it is used to make the refrigerant carbon tetrafluoride, CF4 via the reaction

2COF2(g)⇌CO2(g)+CF4(g),    Kc=8.90

If only COF2 is present initially at a concentration of 2.00 M, what concentration of COF2 remains at equilibrium?

Express your answer with the appropriate units.

Answer 1

Given, the equilibrium reaction,

2COF₂(g) $\rightleftharpoons$ CO₂(g) + CF₄(g) ----------- K_c = 8.90

Initial concentration of COF₂ = 2.00 M

Drawing an ICE chart,

	2COF2	CO2(g)	CF4(g)
I(M)	2.00	0	0
C(M)	-2x	+x	+x
E(M)	2.00-2x	x	x

K_c = [CO₂] [CF₄] / [COF₂]²

8.90 = [x] [x] / [2.00-2x]

8.90 = x² / [2.00-2x]

17.8 - 17.8 x - x² = 0

x² + 17.8 x -17.8 = 0

Solving the quadratic equation,

x = 0.9494

We know,

[COF₂]_eq = 2.00-2x

[COF₂]_eq = 2.00-2(0.9494)

[COF₂]_eq = 0.101 M