Question

The rate of the first-order reaction `X rarr` products is `7.5 xx 10^(-4) mol L^(-1) "min"^(-1)`. What will be value of rate constant when the concentration of `X` is `0.5 mol L^(-1)` ?
A. `8xx10^(-4)`
B. `1.5xx10^(-3)`
C. `2.5xx10^(-5)`
D. `3.75xx10^(-4)`

Answer 1

Correct Answer - B
1st order reaction ,
`7.5xx10^(-4) = K [0.5]`
` therefore k= (7.5xx10^(-4))/(t_(1//2))=1.5xx10^(-3)`