Question

In a first order reaction, the concentration of the reactant decreases form `800 "mol dm"^(-3)` to `50 "mol dm"^(-3)` in `2 xx 10^(4) s`. The rate constant of the reaction (in `s^(-1)`) is
A. (a) `2xx10^(4)`
B. (b) `3.45xx10^(-5)`
C. (c ) `1.386xx10^(-4)`
D. (d) `2xx10^(-4)`

Answer 1

Correct Answer - c
`K=2.303/t"log"C_(0)/C`
`=2.303/(2xx10^(4))"log"800/50`
`=1.38xx10^(-4) sec^(-1)`