Question

Thermal decomposition of a compound is the first order. if 50 % of a sample of the compound is decomposed in 120 minutes. show how long will it take for 90% of the compound to decompose?

Options
A) 399 min
B) 410 min
C) 250 min
D) 120 min

Please say me the correct answer & with clear explanation ​

Answer 1

Answer:

(A) 399 min

Explanation:

For half time the formula is:

K=0.693/t1/2=0.693/120=5.77

*10–3min–1

For a first order reaction

K=(2.303/t)*log*1/a-x

a=100, x=90

5.77*10–3min–1=(2.303/t)*log*100/1

-90

t=2.303/5.77*10–3log10=399 min

Hope this answer will help you.And please mark my answer as brainliest.