Chemistry Class 12 NCERT Solutions: Chapter 4 Chemical-Kinetic Part 10

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Q: 20. For the decomposition of azoisopropane to hexane and nitrogen at , the following data are obtained.

Q_20_Table of the Decomposition of Azoisopropane to Hexane and Nitrogen
Q_20_Table of The Decomposition of Azoisopropane to Hexane and Nitrogen

t(sec)

P(mm of Hg)

Calculate the rate constant.

After time, t, total pressure,

Therefore,

For a first order reaction,

When

When

Hence, the average value of rate constant is

Note: - There is a slight variation in this answer and the one given in the NCERT textbook.

Q: 21. The following data were obtained during the first order thermal decomposition of at a constant volume.

Q_21_Table of Data Were Obtained During the First Order Thermal Decomposition
Q_21_Table of Data were Obtained During the First Order Thermal Decomposition

Experiment

Total pressure/atm

1

0

0.5

2

100

0.6

Calculate the rate of the reaction when total pressure is .

Answer:

The thermal decomposition of at a constant volume is represented by the following equation

After time, total pressure,

Therefore,

For a first order reaction,

When

When ,

Therefore, when the total pressure is , pressure of is

Therefore, the rate of equation, when total pressure is , is given by,