For a reaction, `A rarr B+C`, it was found that at the end of `10` minutes from the start, the total optical rotation of the system was `50^(@)` and when the reaction is complete, it was `100^(@)`. Assuming that only `B` and `C` are optically active and dextrorotatory. Calculate the rate constant of this first order reaction

Options

A. `k = 0.695 "min"^(-1)`
B. `k = 0.0693 sec^(-1)`
C. `k - 0.0693 "min"^(-1)`
D. `k = 0.00693 sec^(-1)`

Answer

C

Explanation

`r_(10) = 50^(@), r_(oo) = 100^(@), r_(0) = 0`
`:. k = (2.303)/(10)"log"((100 - 0)/(100 - 50)) = 0.0695 "min"^(-1)`