Question

12.) Two substances A and B are present such that
[Al. = 4[B], and half life of A is 5 minute and that
of B is 15 minute. If they start decaying at the
same time following first order kinetics how much
time will the concentration of both of them would be
the same?
(2) 10 minute
(1) 15 minute
(3) 5 minute
(4) 12 minute​

Answer 1

Answer:

(1) 15 mint

Explanation:

[B] = x then = [A] = 4x

now.. .

[B] = x/2 ; t = 15mnt

but...

[A] = 2x : t = 5mnt

[A] = x : t = 10mnt

[A] = x/2 t = 15mnt

hence.....

[A] = [B] when t = 15mnts