NEET Chemistry Chemical Kinetics Questions Solved


The gas phase decomposition 2N2O54NO2+ O2 fol- lows the first order rate law.K = 7.5 × 10-3sec-1. The initialpressure of N2O5is 0.1 atm. The time of decomposition of N2O5so that the total pressure becomes 0.15 atm will be-

(A) 54 sec                                                          

(B) 5.4 sec

(C) 3.45 sec                                                       

(D)34.55 sec

A.                          2N2O5  4NO2        + O2Initial pressure      0.1 atm          0                 0pressure at time,t  0.1-xatm 2x atm      x/2atmTotal pressure=  0.1-x+2x+x/2=0.1+3x/2=0.15x=0.1/3

Now, from Ist order kinetics,

t=2.303KlogP0P=2.3037.5×10-3log0.10.1-x=54sec.

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