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Chemical Kinetics question

2021 · Q120
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Chemical Kinetics question

2021 · Q120

NEETChemistryChemical KineticsMCQ+4 / −1
The slope of Arrhenius plot (ln⁡ k v/s1T)\left( {\ln \,k\,v/s{1 \over T}} \right)(lnkv/sT1​) of first order reactino is −-−5 ×\times× 103K. The value of Ea of the reaction is. Choose the correct option for your answer.

[Given R = 8.314 JK−-−1mol−-−1]
  1. A
    −-−83 kJ mol−-−1
  2. B
    41.5 kJ mol−-−1
  3. C
    83.0 kJ mol−-−1
  4. D
    166 kJ mol−-−1
View written solutionFree

Correct answer: B

Arrhenius equation

k=Ae−Ea/RTk = A{e^{ - {E_a}/RT}}k=Ae−Ea​/RT

ln⁡k=ln⁡A+ln⁡e−Ea/RT\ln k = \ln A + \ln {e^{ - {E_a}/RT}}lnk=lnA+lne−Ea​/RT

ln⁡k=ln⁡A−EaR(1T)\ln k = \ln A - {{{E_a}} \over R}\left( {{1 \over T}} \right)lnk=lnA−REa​​(T1​) .... (1)

Slope of ln⁡k \ln k\,lnk vs 1T{1 \over T}T1​ curve,

m=−EaRm = - {{{E_a}} \over R}m=−REa​​

−5×103=−EaR - 5 \times {10^3} = - {{{E_a}} \over R}−5×103=−REa​​

Ea = 5 ×\times× 103 ×\times× 8.314 J/mol

= 41.57 ×\times× 103 J/mol

≃\simeq≃ 41.5 kJ/mol

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