Question

The reaction between CO and H2 is carried out at a different temperature with initial concentrations of[CO] = 0.37 M and [H2]= 0.64 M .
CO(g)+2H2(g)⇌CH3OH(g)
At equilibrium, the concentration of CH3OH is 0.12 M .

Find the equilibrium constant at this temperature.

Answer 1

Let us draw an ICE table for the given reaction

CO (g) + 2 H2 (g) <-----> CH3OH (g)

I	0.37	0.64	0
C	-x	-2x	+x
E	0.37 - x	0.64 - 2x	x

Equilibrium concentration of CH3OH is given as 0.12 M

But from the above ICE table , we have equilibrium concentration of CH3OH as x

Therefore x = 0.12 M

Using this value of x, we can now find equilibrium concentrations of reactants.

Eq. conc. of CO = 0.37 M - x

= 0.37 M - 0.12 M

= 0.25 M

Eq. conc. of H2 = 0.64 M - 2x

= 0.64 - 2*0.12 M

= 0.40 M

[H2]eq = 0.40M, [CO]eq = 0.25M, [CH3OH]eq = 0.12M

Using these values of eq. concentrations, we can now find Kc for the above reaction.

The equation for Kc is written as

Kc = [ CH3OH] / [CO] [ H2]^2

= (0.12) / ( 0.25) ( 0.40)^2

= 0.12/0.04

= 3.0

Equilibrium constant Kc for this reaction is 3.0