Question

The decomposition reaction 2 HI(g) → H2(g) + 12(g), is second order and has a rate constant equal to 1.6 x 10M's at 700 °C. If the initial concentration of HI in the container is 3.4 x 10-M, how many minutes will it take for the concentration to be reduced to 8.0 x 104 M?

Answer 1

Answer : The time taken by the reaction is 12714.46 minutes.

Explanation :

The expression used for second order kinetics is:

`kt=(1)/([A_t])-(1)/([A_o])`

where,

k = rate constant =
`1.6* 10^(-3)M^(-1)s^(-1)`

t = time = ?

`[A_t]` = final concentration =
`8.0* 10^(-4)M`

`[A_o]` = initial concentration =
`3.4* 10^(-2)M`

Now put all the given values in the above expression, we get:

`(1.6* 10^(-3))* t=(1)/(8.0* 10^(-4))-(1)/(3.4* 10^(-2))`

`t=762867.6471s=12714.46min` (1 min = 60 s)

Therefore, the time taken by the reaction is 12714.46 minutes.