MDCAT Chemistry MCQ #2205

A chemist measures the equilibrium concentrations for the H2 + I2 ℑ 2HI reaction at 444°C as [H2]=0.1 M, [I2]=0.1 M, and [HI]=0.4 M. What is the value of Kc?

MDCAT Chemistry MCQ #2205

  1. Question 1

    Q1. A chemist measures the equilibrium concentrations for the H2 + I2 ℑ 2HI reaction at 444°C as [H2]=0.1 M, [I2]=0.1 M, and [HI]=0.4 M. What is the value of Kc?

    • A) 4.0
    • B) 8.0
    • C) 1.6
    • D) 16.0

    Answer: 16.0

    Explanation: Kc equals [HI]^2 / ([H2][I2]); substituting values gives (0.4)^2 / (0.1 * 0.1) = 16. Option A fails by forgetting to square the HI concentration.