Question

For the reaction $R\to P, $ the concentration of a reactant changes from $0.03 M$ to $0.02 M$ in $ 25$ minutes. The average rate of reaction is

• A. $4 \times 10^{-4} \,M\, min ^{-1}$
• B. $4 \times 10^{4} M \,min ^{- 1 }$
• C. $3 \times 10^{-4} M \,min ^{-1}$
• D. $3 \times 10^{4} M\, min ^{-1}$

Answer 1

Answer: (A)

$Average \,rate =\frac{\Delta\left[R\right]}{\Delta t} =\frac{\left[R\right]_{2}-\left[R\right]_{1}}{t_{2} -t_{1}} $
$= - \frac{0,02-0,03}{25} =\frac{\left(-0.01\right)}{25} =4\times10^{-4} M min ^{-1}$