Question

Consider the reaction of hydrogen gas (H2) and iodine gas (I2) to form hydrogen iodide (HI) at a certain temperature. If the initial concentrations of hydrogen and iodine are [H2] = 0.5 M and [I2] = 0.3 M, and the equilibrium concentration of hydrogen iodide is [HI] = 0.1 M, what is the value of the reaction quotient (Qc) for this reaction at this temperature?

Answer 1

The balanced chemical equation for the reaction is:H2 g  + I2 g   2HI g To find the reaction quotient  Qc , we need to use the expression:Qc = [HI]^2 /  [H2] * [I2] Since the equilibrium concentration of hydrogen iodide is [HI] = 0.1 M, we need to determine the equilibrium concentrations of hydrogen and iodine.From the balanced equation, we can see that 1 mole of H2 reacts with 1 mole of I2 to produce 2 moles of HI. Let's use x as the change in concentration for H2 and I2:[H2] = 0.5 - x[I2] = 0.3 - x[HI] = 2xAt equilibrium, [HI] = 0.1 M, so:2x = 0.1x = 0.05Now we can find the equilibrium concentrations of H2 and I2:[H2] = 0.5 - 0.05 = 0.45 M[I2] = 0.3 - 0.05 = 0.25 MNow we can calculate the reaction quotient  Qc :Qc = [HI]^2 /  [H2] * [I2] Qc =  0.1 ^2 /  0.45 * 0.25 Qc = 0.01 / 0.1125Qc  0.089So, the value of the reaction quotient  Qc  for this reaction at this temperature is approximately 0.089.