Question

thermal decomposition of a compound is of first order if 50% of a sample of a compound with this post in 120 minutes , then time taken for 99.9% completion is​

Answer 1

Half life of reaction =120 min

We know that,

k=t1/20.693=1200.693=5.77×10−3min−1

Applying first order reaction equation,

t=k2.303log10a−xa

If a=100, x=90 or (a−x)=10,

So, t=5.77×10−32.303log1010=5.77×10−32.303=399min.