Question

The time for half life period of a certain reaction $A \longrightarrow Products$ is 1 hour. 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 a zero order reaction ? (a) 4 h (b) 0.5 h(c) 0.25 h (d) 1 h

Answer 1

For a zero order reaction ,k= rate constant

When t=ty2, then x=|A|o2

Given that [A0]=2M

ty2=1hr,K=1

∴K=|A|02×ty2=22×1

=1mol.L−1.hr−1

Now, change in conc (x)=0.50−0.25

=0.25M

∴t=xk=0.251=0.25hr

Hence c is the correct answer.