What will be the initial rate of a reaction if its rate constant is 10−3 min−1 and the concentration of the reactant is 0.2 mol dm−3?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 0.0002 mol dm−3 min−1
The unit of the rate constant, min−1 (time−1), shows a first order reaction, so the rate is proportional to the first power of the reactant concentration:
\( \displaystyle \text{Rate}=k[\mathrm{A}] \)
\( \displaystyle \text{Rate}=(10^{-3}\ \mathrm{min^{-1}})\times(0.2\ \mathrm{mol\ dm^{-3}}) \)
\( \displaystyle \text{Rate}=2\times10^{-4}\ \mathrm{mol\ dm^{-3}\ min^{-1}}=0.0002\ \mathrm{mol\ dm^{-3}\ min^{-1}} \)