# Chemistry Class 12 NCERT Solutions: Chapter 4 Chemical-Kinetic Part 11 (For CBSE, ICSE, IAS, NET, NRA 2022)

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Q: 22. The rate constant for the decomposition of at various temperatures is given below:

0 | 20 | 40 | 60 | 80 | |

Draw a graph between ln and and calculate the values of A and .

Predict the rate constant at .

Answer:

From the given data, we obtain

0 | 20 | 40 | 60 | 80 | |

273 | 293 | 313 | 333 | 353 | |

Slope of the line,

According to Arrhenius equation,

Slope

Again,

When

Then,

Therefore,

When

Then,

Therefore,

Again, when

Therefore,

Q: 23. The rate constant for the decomposition of hydrocarbons is . If the energy of activation is , what will be the value of pre-exponential factor.

Answer:

According to the Arrhenius equation,

Therefore,