JEE Main 2019ChemistryChemical KineticsHardMCQ

JEE Main 2019 — Chemical Kinetics Question with Solution

JEE Main 2019 (09 Jan Shift 2)

Question

For the reaction, 2A+B→ products, when the concentration of A and B both were doubled, the rate of the reaction increased from 0.3 mol L-1s-1 to 2.4 mol L-1s-1.  When the concentration of A alone is doubled, the rate increased from 0.3 mol L-1s-1 to 0.6 mol L-1s-1.

Which one of the following statements is correct?

Choose an option

Show full solutionCorrect option: A
Correct answer
AOrder of the reaction with respect to B is 2

Step-by-step explanation

2A+B→C

Initial r1=kAxBy=0.3 m/sec ...(i)

r2=k2Ax2By=2.4 ...(ii)

r3=k2AxBy=0.6 ...(iii)

From (i) ÷ (iii)

12x1y=0.30.6

12x=12

x=1

(ii) ÷ (iii)

r2r3=2.40.6=2y

4=2y

y=2

The order of reaction w.r.t. A=1 and w.r.t. B=2

Total order of reaction =1+2=3

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About this question

This is a previous-year question from JEE Main 2019, covering the Chemical Kinetics chapter of Chemistry. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.