Q52 / 160 · JIPMER 2012 · Chemistry
For a zero order reaction
- Correct answerA$t_{1 / 2} \propto R_0$
- B$t_{1 / 2} \propto 1 / R_0$
- C$t_{1 / 2} \propto R_0^2$
- D$t_{1 / 2} \propto 1 / R_0^2$
Solution
For a zero order reaction
rate, $-\frac{d[R]}{d t}=k$
On integrating, we get
$[R]=-k t+[C]$
When $t=0,[R]=\left[R_0\right]$
$\therefore \quad[C]=\left[R_0\right]$
$\therefore \quad[R]=-k t+\left[R_0\right]$
When, $t=t_{1 / 2},[R]=\frac{\left[R_0\right]}{2}$
$\therefore \quad \frac{\left[R_0\right]}{2}-\left[R_0\right]=-k t_{1 / 2}$
$\therefore \quad t_{1 / 2}=\frac{\left[R_0\right]}{2 k}$
$t_{1 / 2} \propto\left[R_0\right]$
Hence, the correct answer is option: 'A'.