`1^(st)` order reaction Find the rate constant for the reaction having initial and final concentration are 11.9 and 4.15 at 20 minutes.

Explanation

`k = (2.303)/(t) "log" ([V]_0)/([V])`
Here `V_0 =11.4 `
`t = 10 "min", V_t = 6.9 `
`therefore k = (2.303)/(10) "log" (11.4)/(6.9) implies k = (2.303)/(10) xx 6.5182 `
`k = 10.05028 "min"^(-1)`
`t = 20 "min", V_t = 4.15 `
`because k = (2.303)/(20) "log" (11.9)/(4.15)`
`k = 0.11515 xx 0.43918 `
`k = 0.0505726 "min"^(-1)`
Since the value of k comes constant to be above constant the `r alpha^(n)` is of first order.