Question

a first order reaction completes 50% in 50 minutes. How much time it will take for 90% of completion

Answer 1

Explanation:

For a first order reaction,

t21=k0.693

⇒k=250.693=0.028min−1

Now using first order eqution,

K=t2.303log[R][R°]

⇒t=0.0282.303log0.2[R°][R0](∵[R]=100100−80[R°])

t=0.0645×log5=57.49min