Question

In the following gaseous phase first order reaction
A(g)----B(g) + C(g)
Initial pressure was observed to be 200 mmHg and
after 20 minutes, it changed to 300 mmHg. The rate
constant for the reaction is
​

Answer 1

Answer:

100 mm Hg

Explanation:

                                                                               Final Pressure

                     A (g) --------->        B (g)  +    C (g)    

Initial    200 mm Hg                                                   200 mm Hg

Final     (200-x) mm Hg       x mmHg      x mmHg     300 mm Hg

We know that initially the pressure was 200 mm Hg. It was because of A only.

After 20 mins the pressure becomes 300 mm Hg. Let's consider x and x pressure has been formed due to B and C and x has been reduced from A.

The value of x will come out to be 100 mm Hg.

The rate constant can be found by the product of partial pressure of product gases to the power of stoichiometry divided by the product of pressure of reactant gases to the power of their stoichiometric coefficients.

$K=\frac{100^1*100^1}{100^1}=100mmHg$