NEET Chemistry Chemical Kinetics Questions Solved


A first order reaction was started with a decimolar solution of the reactant. After 8 minutes and 20 seconds, its concentration was found to be M/100. Determine the rate constant of the reaction. 

(A) 4.6 × 10-3sec-1                                      

(B) 16.6 × 10-3 sec-1

(C) 24.6 × 10-3 sec-1                                   

(D) 40.6 × 10-3 sec-1

(A) Here a= 0.1 M

a-x=M100=0.01 M

t=8 minutes 20 seconds=500 seconds 

Substituting  the values in the first order reaction

k=2.303tlog aa-x=2.303500log 0.10.01=2.303500log 10=4.6061000×1=4.6×10-3sec-1

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