Unit-4 Chemical Kinetics/Question papers 2015 to 2022/mbose

Questions: 2022

  • Derive the integrated rate equation for the first order reaction. Hence prove that half-life period is independent of initial concentration of the reactant.
  • Time for half-life change for a first order reaction is 25 sec. Find the time taken for the completion of 99.9% reaction.
  • Calculate the overall order of a reaction which has the rate expression of Rate =K[A]1/2[B]3/2
  • The rate constant for a reaction of zero order in A is 0.0030 mol/L/sec. How long will it take for the initial concentration to fall from 0.10M to 0.075M?

Questions: 2021

  • The inversion of cane sugar is represented by the reaction,

C12H22O11 + H2O ———>  C6H12O6 + C6H12O6

(i) What is the order of this reaction?

(ii) Give one condition that determines the order of this reaction.

  • For zero order reaction, R –> P, derive the integrated rate equation and find its half-life time period.

Questions: 2020

  • For a reaction, the first order rate constant at 600 K is 1.60 x 10-5 S-1. Its energy of activation is 209 kJ/mol. Calculate the rate constant of the reaction at 700 K.
  • Define half-life period of a chemical reaction.
  • What is the overall order of the reaction: CHCl3 + Cl2 → CCl4 + HCl, with rate expression, r = k [CHCl3][Cl2]½ ? Is this reaction an elementary reaction? Give reason.
  • For first order reaction, prove that t99% =10 x t50% or t99.99% = 10 t½
  • Write Arrhenius equation and indicate the terms involved.

Questions:2019

  • When does the average rate of a reaction become equal to instantaneous rate? 1
  • Write any one condition under which a bimolecular reaction may be kinetically of first order.
  • Half-life period of a reaction increases with increase in initial concentration. Predict the order of the reaction.
  • Decomposition of a compound follows first order kinetics. If it takes 15 minutes for 20% of original substance to decay, calculate – (i) Rate constant & (ii) The time at which 10% of the reactant remains undecayed.

Questions: 2018

  • Calculate the overall order of a reaction which has the rate expression, r = k [A]1/2 [B]3/2.
  • What is the rate determining step of a reaction?
  • What is the order of reaction whose rate constant has the same unit as the rate of reaction?
  • Thermal decomposition of a compound is of first order. 50% decomposes in 120 minutes. How long will it take for 90% decompose?

Questions: 2017

  • Write any tow differences between order and molecularity of a reaction.
  • Write Arrhenius equation which relates the rate constant with temperature.
  • A first order reaction takes 40 minutes for 30% decomposition. Calculate half-life.

Questions: 2016

  • For first order reaction, it takes 5 minutes for the initial concentration of 0.6 mol /L to become 0.4 mol /L. How long will it take for the initial concentration to become 0.3 mol /L?
  • Drive the integrated rate equation for the first order. Hence prove that half-life period for it is independent of initial concentration.

Questions: 2015

  • Derive the general expression for the rate constant k for a first-order reaction.
  • The initial concentration of N2O5 in the following first-order reaction                                N2O5 (g) → 2NO2 (g) + ½O2 (g), was 1.24 x 10-2 mol /L at 318 K. The concentration of N2O5 after 60 minutes was 0.20 x 10-2 mol /L. Calculate the rate constant of the reaction at 318 K.
  • Define pseudo first-order reaction. Give an example.
  • The time required for 10% completion of a first-order reaction at 298 K is equal to that required for its 25% completion at 308 K. Calculate the energy of activation.
  • What is meant by half-life period of a chemical reaction? Give the expression for half-life of a first-order Reaction.
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