Question

Which of the following statements are correct about half-life period.

• A. It is proportional to initial concentration for zeroth order
• B. $\text{Average life}=1.44\times \text{half-life}$; for first order reaction
• C. Time of $75\%$ reaction is thrice of half-life period in first order reaction
• D. $99.9\%$ reaction takes place in $100$ minutes for the case when rate constant is $0.0693{\text{min}}^{-1}$

Answer 1

Answer: (A), (B), (C), (D)

$99.9\%$ reaction takes place in $100$ minutes for the case when rate constant is $0.0693{\text{min}}^{-1}$

$\left(a\right)t_{1/2}\propto \frac{1}{a^{n-1}};\left(b\right)T=\frac{1}{\lambda }=\frac{t_{1/2}}{0.693}=1.44t_{1/2};\left(c\right)t_{3/4}=2t_{1/2};\left(d\right)=t_{99.9\text{\%}}=10t_{1/2}=10\left(\frac{0.693}{0.0693}\right)=100\text{min}$