Question

For the zero order reaction, $\text{A}\to \text{B}+\text{C}$ ; initial concentration of A is 0.1 M. If [A] = 0.08 M after 10 minutes, then it's half life and completion time are respectively

• A. $10\text{min}\text{, }20\text{min}$
• B. $25\text{min}\text{, }50\text{min}$
• C. $2\times 10^{-3}\text{min}\text{, }4\times 10^{-3}\text{min}$
• D. $250\text{min}\text{, }500\text{min}$

Answer 1

Answer: (B)

For zero order reaction $\Rightarrow {\text{C}}_{\text{t}}={\text{C}}_0-\text{kt}$

So, $\text{k}=\frac{{\text{C}}_0-{\text{C}}_{\text{t}}}{\text{t}}=\frac{0.1-0.08}{10}=2\times 10^{-3}$

${\text{T}}_{1/2}=\frac{{\text{C}}_0}{2\text{k}}=\frac{0.1}{2\times 2\times 10^{-3}}=25\text{min}$

$T_{100\%}=\frac{C_0}{k}=\frac{0.1}{2\times 10^{-3}}=\frac{100}{2}=50min$