The time for half-life period of a certain reaction, `A rarr` products is `1 h`. When the initial concentration of the reactant `'A'` is `2.0 "mol" L^(-1)`, how much time does it take for its concentration to come from `0.50` to `0.25 "mol" L^(-1)`, if it is zero order reaction ?

Options

A. `4h`
B. `0.5h`
C. `0.25h`
D. `1h`

Answer

C

Explanation

For zero order reaction
`t_(1//2)propa` (initial concentration)
`2.00Moverset(t_(1//2)=1h)(rarr)1.00Moverset(t_(1//2)=0.5h)(rarr)0.5Moverset(t_(1//2)=0.25h)(rarr)0.25h`
Alternatively
`k_(0)=([R]_(0))/(2t_(t//2))=(2M)/(2(1h))`
`=1Mh^(-1)`
Mext
`t=([R]_(0)-[R}0/(k)=((0.50M)-(0.25M))/(1mh^(-1)`
`=0.25h`