NEET Chemistry Chemical Kinetics Questions Solved

BOARD

A first order reaction has a rate constant of 0.0051 min-1. If we begin with 0.10 m concentration of the reactant, what concentration of reactant will remain in solution after 3 hours?

Given :  [R]= 0.10 M,    t = 3 hrs = 180 min

           K = 0.0051 min-1       [R] = ?

using formula : K =2.303tlog [R][R]

                0.0051 = 2.303180log 0.10[R]

            or     log 0.10[R] = 0.0051×1802.303

            or   log 0.10[R] = 0.9182.303 = 0.3986

            or  log 0.10[R] = antilog(0.3986)

            or log 0.10[R] = 2.503

           [R] = 0.102.503 = 0.0399

 Concentration of reactant remains 0.040 M

      

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