Question

5)The rate constant of the reaction, A -----> 2 B is 6.93 x10-2 s-1. If initial concentration of A is 2 M then the time in which B becomes 2 M is

10 s

20 S

10 min

20 min​

Answer 1

Answer:

The rate constant has unit mole per second which indicates zero order reaction.

x = kt

The concentration of B after 20 minutes is 20×60×0.6×10

−3

=0.72M

Answer 2

Answer:

It will take 10 seconds to give 2M of B.

Explanation:

According to the reaction:

1M of A reacts to give 2M of B

Initial concentration of A = 2M

Therefore, 1M of A will be consumed and 1M of A will be residue.

Time is taken by the reaction to reach 2M of B = t

The rate constant of the reaction = $6.93\times10^{-2}s^{-1}$

As we know that

$\[\begin{gathered} \ln \left( {\frac{{{A_o}}}{{{A_t}}}} \right) = Kt \hfill \\ \ln \left( {\frac{2}{1}} \right) = 6.93 \times {10^{ - 2}} \times t \hfill \\ 0.693 = 6.93 \times {10^{ - 2}} \times t \hfill \\ t = 10s \hfill \\ \end{gathered} \]$

Therefore, it will take 10 seconds to give 2M of B.