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OPRA Pharmacokinetics and Pharmacodynamics QUESTION #3834
Question 1
A drug undergoing first-order hydrolysis has an initial concentration of $0.16$ M, which falls to $0.04$ M after $6$ days. What is its half-life?
  • $1$ day
  • $2$ days
  • $3$ days✔️
  • $4$ days
Correct Answer Explanation
$0.16 \rightarrow 0.08$ M (one half-life) $\rightarrow 0.04$ M (two half-lives). Two half-lives $= 6$ days, therefore half-life $= 3$ days.