Hidden Assumptions That Make Equilibrium Calculations Easier What Do We

Multiple Choice

Hidden Assumptions that make Equilibrium Calculations Easier What Do We Do When the Approximation Fails?
based on the following reaction:

2H₂O(g) 2H₂(g) + O₂(g)
K_c = 2 x 10^-42 (at 25^oC)
-Starting with 0.10 M H₂O(g) , what would be the best strategy for solving for the equilibrium concentrations of H₂O, H₂ and O₂?

A) Since the change in the concentrations are expected to be large going to equilibrium, the equation will have to be solved exactly.
B) Since the changes in the concentrations are expected to be large going to equilibrium, it is best to assume that all of the H₂O(g) is converted to products and then calculate the equilibrium concentration.
C) Since the changes in concentrations are expected to be small going to equilibrium, it is best to assume that the changes will be small relative to the initial concentration of H₂O(g) .
D) Since the changes in concentrations are expected to be small going to equilibrium, it is best to assume that the changes will be large relative to the initial concentration of H₂O(g) .
E) There is no reasonable way to even approximate the answer to this problem.