Question

The rate constant for a particular second-order reaction is 0.47 M-1s-1. If the initial concentration of reactant is 0.25 mol/L, it takes __________ s for the concentration to decrease to 0.13 mol/L.

Answer 1

Answer : The time taken by the reaction is 7.856 seconds.

Explanation :

The expression used for second order kinetics is:

$kt=\frac{1}{[A_t]}-\frac{1}{[A_o]}$

where,

k = rate constant = $0.47M^{-1}s^{-1}$

t = time = ?

$[A_t]$ = final concentration = 0.13 mole/L = 0.13 M

$[A_o]$ = initial concentration = 0.25 mole/L = 0.25 M

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

$0.47\times t=\frac{1}{0.13}-\frac{1}{0.25}$

$t=7.856s$

Therefore, the time taken by the reaction is 7.856 seconds.