MDCAT Chemistry MCQ #5143

A reaction is 50% complete in 20 minutes. If it is first-order, how long will it take for 75% completion?

MDCAT Chemistry MCQ #5143

  1. Question 1

    Q1. A reaction is 50% complete in 20 minutes. If it is first-order, how long will it take for 75% completion?

    • A) 40 min
    • B) 60 min
    • C) 30 min
    • D) 45 min

    Answer: 40 min

    Explanation: For a first-order reaction, 50% and 75% completion correspond to 1 and 2 half-lives, so 2 × 20 = 40 min.