Two substances, 'A' and ‘B' are initially present as `[A_o] = 8[B_o]` and `t_(1/2)` for the first-order decomposition of ‘A’ and ‘B' are 10 and 20 min, respectively. If they start decomposing same time, after how much time, the concentration of both of them would be same?
| A. |
20 min |
| B. |
40 min |
| C. |
60 min |
 |
| D. |
200 min |
For first order decomposition `C_t=C_0(1/2)^N` :where N is number of half life periods.
Given `[A_0]=8[B_0]`= For 'A', `N_A=60/10=6`
`C_A=C_0(1/2)^6=(8B_0)/64=B_0/8` For `B : N_B=60/20=3`
`C_B=B_0(1/2)^3=B/8`
After 60 mins the concentration of both 'A' and 'B' will be equal