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. `0.5 h`
C. `0.25 h`
D. `1h`

Answer

c

Explanation

Half -life for a zero -order reaction is given by
`t_(1//2) = ([A_(0)])/(2k)`
[where `[A_(0)] =` initial concentration of reactant]
` rArr k_(0) = ([A]_(0))/(2t_(1//2)) = (2.0 mol L^(-1))/(2 xx 1h) = 1.0` and `L^(-1)h^(-1)`
Rate constant for a zero- order reaction is given by
`k = (1)/(t) [(A_(0)) - (AI)]`
`rArr t = (1)/(k) [(A_(0)) -(A)]`
`t = ((0.50)-(0.25)mol L^(-1))/(1 mol L^(-1)h^(-1))`
`rArr t = 0.25 h`