Gaseous hydrogen and iodine are placed in a closed container at 425 degrees Celsius. The reactants react to produce the gaseous compound hydrogen iodide, which partially decomposes back into hydrogen and iodine gas as shown below.

Assuming those numbers you listed are the equilibrium values, your answer is correct but only if that is true.

To determine the equilibrium constant (Kc) at this temperature, we need to use the formula:

Kc = [HI]^2 / ([H2] * [I2])

Given the following data:
[HI] = 2.53 * 10^-4 M
[H2] = 3.79 * 10^-4 M
[I2] = 3.79 * 10^-4 M

Substituting these values into the formula, we have:

Kc = (2.53 * 10^-4)^2 / ((3.79 * 10^-4) * (3.79 * 10^-4))

Simplifying:

Kc = (6.40 * 10^-8) / (5.71 * 10^-7)

Dividing these numbers, we get:

Kc = 0.111

So, the equilibrium constant (Kc) at this temperature is 0.111. Note that the value you provided (0.446) is not correct according to the data given.