Given,
Half life period for the reaction, t12=1 hr
Initial concentration, [Ao]=2 mol L−1
Again, order of the reaction is zero.
Thus, t12=[Ao]2k
⇒k=[Ao]2t12=22×1=1 mol L−1 hr−1
For, zero order reaction,
k=1t([Ao]−[A])
⇒t=1k([Ao]−[A])=11[0.50−0.25]=0.25 hr