A) 5 hours
B) 7.5 hours
C) 10 hours
D) 20 hours
Correct Answer: B
Solution :
\[k=\frac{0.693}{45}{{\min }^{-1}}=\frac{2.303}{{{t}_{99.9%}}}\log \frac{a}{a-0.999a}\] or \[{{t}_{99.9%}}=\frac{2.303\times 45}{0.693}\log {{10}^{3}}=448\,\,\min \approx 7.5\,\,hrs\]You need to login to perform this action.
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