The rate constant of a zero order reaction is `0.2` mol `dm^(-3) "min"^(-1)` if the concentration of reactants after 30 minutes in `0.5` mol `dm^(-3)` then the initial concentration would be

Options

A. `0.65` mol `dm^(-3)`
B. 65 mol `dm^(-3)`
C. `3.0` mol `dm^(-3)`
D. `6.5` mol `dm^(-3)`

Answer

D

Explanation

For a zero order reaction
`k=(1)/(t)[[A]_(0)-[A]]`
`0.2=(1)/(30)[[A]_(0)-0.5]`
`[A]_(0)=6.5 "mol dm"^(-3)`.