The hydrolysis of methyl acetate in alkaline solution
`CH_(3)COOH_(3)+OH^(-)rarrCH_(3)COO^(-)+CH_(3)OH` followed rate `=k[CH_(3)COOCH_(3)][OH^(-)]` where `k=0.137` L `"mol"^(-1)s^(-1)` at 298 K A reaction mixture was prepared to have initial concentrations of methyl acetate and `OH^(-)` of `0.050` M each The time taken for `5.0%` of the methyl acetate to be hydrolysed at 298 K is (assume that there is no change in the rate during this interval)

Options

A. `7.4s`
B. `4.7 s`
C. `4.7` min
D. `0.47` min

Answer

A

Explanation

Initial rate `=k[CH_(3)COOCH_(3)][OH^(-)]`
`=(0.137NM^(-1)s^(-1))(0.050M)^(2)`
`=3.4 xx 10^(-4)"M s"^(-1)`
Time taken for 5 % of ester to hydrolyse
`t = ((0.050M)xx(5//100))/(3.4xx10^(-4)"Ms"^(-1))=7.4 s`.