The rate constant of the reaction A→B is 0.6×10−3 mole per litre per second. If the concentration of A is 5 M, then concentration of B after 20 minutes is:

The reaction A→B is a first order reaction, as it only involves one reactant. The rate of a first order reaction is given by the equation:

rate = k[A]

where k is the rate constant and [A] is the concentration of A.

Given that k = 0.6×10−3 mole per litre per second and [A] = 5 M, we can substitute these values into the equation to find the rate:

rate = (0.6×10−3 mole/litre/second) * 5 M = 3×10−3 mole/litre/second

The rate of the reaction is the change in concentration of B per unit time. Therefore, the concentration of B after t seconds is given by:

[B] = rate * t

We are asked to find the concentration of B after 20 minutes. First, we need to convert 20 minutes to seconds:

20 minutes = 20 * 60 = 1200 seconds

Then we can substitute the values of the rate and t into the equation to find [B]:

[B] = (3×10−3 mole/litre/second) * 1200 seconds = 3.6 mole/litre

Therefore, the concentration of B after 20 minutes is 3.6 M.