Question

Select the best single answer.

The water-gas shift reaction plays a central role in the chemical methods for obtaining cleaner fuels from coal: CO(g) + H₂O(g) ⇌ CO₂(g) + H₂(g)

At a given temperature, K_p = 2.7. If 0.13 mol of CO, 0.56 mol of H₂O, 0.62 mol of CO₂, and 0.47 mol of H₂ are put in a 2.0−L flask, in which direction does the reaction proceed?

The reaction will proceed to the right OR the reaction is at equilibrium?

Answer 1

Given reaction is:

CO(g) + H₂O(g) CO₂(g) + H₂(g)

Molarity = moles / Volume

[CO] = 0.13 mol/ 2.0 L = 0.065 M

[H₂O] = 0.56 mol/ 2.0L = 0.28 M

[CO₂] = 0.62 mol/ 2.0 L = 0.31 M

[H₂] = 0.47 mol / 2.0 L = 0.235 M

K_c = ([CO₂]*[H₂]) / ( [H₂O][CO]) = (0.31*0.235)/(0.065*0.28) = 4

Now, Moles of gaseous reactant = Moles of Gaseous product

so, K_p = K_c = 4 = Q(say)

But given K_p = 2.7 < Q

Reaction is not at equilibrium

So, reaction will shift backward to give more reactants i.e. toward left