Q.

In a reaction A + B → C, initial concentrations of A and B are related as [A]0=8[B]0. The half-lives of A and B are 10 min and 40 min, respectively. If they start to disappear at the same time, both following first order kinetics, after how much time will the concentration of both the reactants be same            [2025]

1 60 min  
2 80 min  
3 20 min  
4 40 min  

Ans.

(4)

[A]0

8 M10 min4 M10 min2 M10 min1 M10 min0.5 M

[B]0

1 M40 min0.5 M