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=6.90

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

Answer 1

Kc for 2COF2 (g)<----> CO2(g) +CF4(g)   =6.9

Kc= [CO2] [CF4]/ [COF2]² = 6.9

Initial

COF2   : 2M   CO2 : 0       CF4 :0

Equilibrium le , x= molarity of CO2= CF4 for every 1 mole of CO2 formed, there will be 2 moles of COF2 that undergo reaction

COF2 : 2-2x         CO2 : x         CF4: x

x²/ (2-2x)²= 6.9

taking square root on both sides

x/ (2-2x)= 2.63

x= 2.63*(2-2x)

x =2.63*2- 2.63*2x

6.26x= 2.63*2

x= 5.26/6.26 =0.84

at equilibrium [COF2] =2-2*0.84= 0.32M