Sponsor Area

Chemical Kinetics

Question
CBSEENCH12010113

The following data were obtained during the first-order thermal decomposition of SO2Cl2 at a constant volume:


SO2Cl2(g)--->  SO2(g) + Cl2(g)

Experiment

Time/s-1

Total pressure/atm

1
2

0
100

0.4
0.7

 Calculate the rate constant. (Given :  log 4 = 0.6021, log 2 = 0.3010)

Solution

The thermal decomposition of SO2Cl2 at a constant volume is represented by the following equation:  
space space space space space space space space space space space space space space space space space space space space SO subscript 2 Cl subscript 2 left parenthesis straight g right parenthesis space rightwards arrow space space SO subscript 2 left parenthesis straight g right parenthesis space space plus Cl subscript 2 space left parenthesis straight g right parenthesis

At space straight t space equals space 0 space space space space space space space space straight P subscript 0 space space space space space space space space space space space space space space space space space space space 0 space space space space space space space space space space space space space space 0
At space straight t equals space space straight t space space space space space space space space straight P subscript 0 minus straight p space space space space space space space space space space space space space space straight p space space space space space space space space space space space space space space straight p

After space time space straight t comma space total space pressure comma

straight P subscript straight i equals space left parenthesis straight P subscript 0 minus straight p right parenthesis space plus straight p plus straight p
straight P subscript straight t space equals space straight P subscript 0 space plus straight p

Which space space on space rearrangement space gives colon
straight p equals space straight P subscript straight t minus straight P subscript 0

Therefore comma
straight P subscript 0 minus straight p space equals straight P subscript 0 minus left parenthesis straight P subscript straight t minus straight P subscript 0 right parenthesis
equals 2 straight P subscript 0 minus straight P subscript straight t
For space straight a space first space order space reaction comma
straight k equals fraction numerator space 2.303 over denominator straight t end fraction log space fraction numerator straight P subscript 0 over denominator straight P subscript 0 minus straight p end fraction

equals space fraction numerator 2.303 over denominator straight t end fraction log space fraction numerator straight P subscript 0 over denominator 2 straight P subscript 0 minus straight P subscript straight i end fraction

When space straight t space equals space 100 straight s

straight k equals fraction numerator 2.303 over denominator 100 end fraction log space fraction numerator 0.4 over denominator 2 space straight x space 0.4 space minus 0.7 end fraction space equals 1.38 space straight x space 10 to the power of negative 2 end exponent space straight s to the power of negative 1 end exponent