Consider the following reaction:

2 HI (g) → H2 (g) + I2 (g)
Assume that an experiment is carried out in which the starting concentration of HI (g) is 0.100 mol/L. No
products are present at the beginning of the reaction. When equilibrium is established, the concentration of
H2 (g) is 1.41 x 10-2 mol/L. Calculate the equilibrium constant for the above reaction.

.................2 HI (g) → H2 (g) + I2 (g)

I................0.1.............0...........0
C.............-2x..............x...........x
E...........0.1-2x...........x...........x

Write the expression for Kc, substitute the E line from the above, substitute 1.41E-2 for H2 and I2 . evaluate 0.1-2x and solve for Kc.

To calculate the equilibrium constant for the given reaction, we need to use the concentration of reactants and products at equilibrium. In this case, we are given the initial concentration of HI (g) as 0.100 mol/L and the equilibrium concentration of H2 (g) as 1.41 x 10^-2 mol/L.

The equilibrium constant (Kc) for a reaction is expressed using the concentrations of the reactants and products at equilibrium. For the given reaction,

2 HI (g) → H2 (g) + I2 (g)

The equilibrium constant expression is:

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

Substituting the values we know:

Kc = (1.41 x 10^-2) * (x) / (0.100)^2

Here, 'x' represents the concentration of I2 at equilibrium. Since we are not given the value of x directly, we need to find it using the stoichiometry of the reaction.

From the balanced equation, we can see that the molar ratio between HI and I2 is 1:1. So, the concentration of I2 at equilibrium will also be 'x'. Therefore, we can write:

Kc = (1.41 x 10^-2) * (x) / (0.100)^2

Now, we can solve for x by rearranging the equation:

Kc = (1.41 x 10^-2) * (x) / (0.100)^2

Kc = (1.41 x 10^-2) * (x) / 0.0100

x = Kc * 0.0100 / (1.41 x 10^-2)

x = 0.0100 * Kc / 1.41 x 10^-2

Now, we can substitute this value of x back into the expression for Kc:

Kc = (1.41 x 10^-2) * (0.0100 * Kc / 1.41 x 10^-2) / (0.100)^2

Simplifying the expression, we get:

Kc = 0.0100 * Kc / (0.100)^2

Kc = 0.0100 / (0.100)^2

Kc = 0.0100 / 0.0100

Kc = 1

Therefore, the equilibrium constant for the given reaction is 1.