Chemical kinetics Questions and Answers

51 On intreasing the temperature the rate of a reaction Malways increases b always decreases c first increases and then decreases d may increase or decrease depending upon the nature of the reactic

OIS 182 166 H g O g H O AH2 68 32kCal Heat of vapourisation of water at 1 atm and 25 C is 10 52 kCal The standard heat of formation in kcal of 1 mole of water vapour at 25 C is 1 10 52 2 78 84 3 57 80 4 57 80

74 A reaction is of first order After 100 minutes 75 gm of the reactant A are decomposed when 100 gm are taken initially calculate the time required when 150 gm of the reactant A are decomposed the initial weight taken is 200 gm 1 100 minutes 3 150 minutes 2 200 minutes 4 175 minutes CK0081 81 A O O 1 2 3

of 97 97 For a reaction in which case the activation energies of forward and reverse reactions are equal 1 AH 0 2 AS 0 3 The order is zero 4 There is no catalyst CK0107

3 1 25 x 10 min CK0067 A graph between t and concentration for nth orde reaction is a straight line Reaction of this nature is completed 50 in 10 minutes when concentration is 2 mol L This is decomposed 50 in t minutes at 4 mol L n and t are respectively t 4 4 x 105 min 1 0 20 min 3 1 20 min conc 2 1 10 min 4 0 5 min CK0068

reaction is 1 0 2 1 3 2 4 3 CK0071 5 Which of the following statement is not correct for the reaction whose rate is r k rate constant 1 rate of reaction is independent of concentration of reactant 2 2 of reaction does not depend upon concentration of reactant 3 rate constant is independent of concentration of reactant 4 this is zero order reaction

CK0132 2 The rate of the reaction 2N O5 4NO O can be written in three ways k N Osl d N O dt d NO dt k N O d 0 k N Osl dt The relationship between k and k and between k and k are 1 k kk k 2 k 2kk k 3 k 2k kk 2 4 k2k k 2k What double to 35 1 15 3 26 18 The deterr graph 1 12 In

CK0089 2 Chemical reaction occurs as a result of collision between reacting molecules Therefore the reaction rate is given by 1 Total number of collisions occuring in a unit volume per second 2 Fraction of molecules which possess energy less than the threshold energy 3 Total number of effective collisions 4 Temperature

10 Pre Medical Chemistry NEET UG 2019 Odisha 0 A first order reaction has a rate constant of 2 303x10 3 The time required for 40g of this 3

4 Equal to AH 3 More than AH CK0100 2 The rate of reaction increases to 2 3 times when the temperature is raised from 300 K to 310 K If K is the rate constant at 300 K then the rate constant at 310 K will be equal to 1 2 k 2 k 3 2 3 k 4 3 k

The decomposition of N O in CCI at 318K has been studied by monitoring the concentration of N O5 in the solution Initially the concentration of N O5 is 3 32 mol L and after 120 minutes it is reduced to 1 04 mol L 1 The reaction takes place according to the equaiton 2N O g 4NO g O g What is the rate of production of O g in terms of hours 1 1 14 mol L h1 2 0 57 mol L h 3 2 28 mol L h 4 None of these

r C ALLEN 14 In a reaction A B Product rate is doubled when the concentration of B is doubled and rate increased by a factor of 8 when the concentrations of both the reactants A and B are doubled rate law for the reaction can be written 1 Rate KA B 3 Rate k A B as 2 Rate AB 4 Rate KA BF

21 The rate of a first order reaction 0 04 mol L at 10s and 0 03 mol L s at 2 s after initiation of the reaction The half life peri of the reaction is 1 24 1 s 3 44 1 s 2 34 1 s 4 54 1 s

ALLEN 77 Correct statement about first order reaction is 1 completion finite 2 1 2 3 Unit of K is mole lit s 4 2 x K constant at given temperature

The overall order of the reaction will be 2 0 1 2 3 1 5 4 1 CK0159 25 A first order reaction has a specific reaction rate of 102 s How much time will it take for 20 g of the reactant to reduce to 5 g 1 138 6 s 2 346 5 s 3 693 0 s 4 238 6 s CK0160

en by NaOH fRCI are of of the 0035 41 12 K for a zero order reaction is 2 x 10 mol L s If the concentration of the reactant after 25 s is 0 5 M the initial concentration must have been 1 0 5 M 3 12 5 M Th citic of 2 1 25 M 4 1 0 M o CK0043 SECURE CK0044

the reactions 5Br aq BrO aq 6H1 aq 31 Ja 3110 1 Rate of disappeance of Br aq is 1 5 x 10 mol 1 sec Rate of apperaance of Br aq is 1 3 x 10 mol L s 2 6 x 102 mol L1 s 3 9 x 10 mol L 4 4 5 x 102 mol L 11

11 For a first order reaction half life periods are 5000 and 1000 seconds at300 K and 310 K temp respectively Energy of activation 1 12 46 KJ mol 1 2 124 46 KJ mol 4 12 46 KJ mol 3 46 12 KJ mol 12 The experimental data for the reaction 2A B 2AB are as follows Rate law expression will be A mol L 1 0 50 0 50 1 00 1 rate KIB 3 rate K A B mol 1 1 0 50 1 0 1 0 Rate mol 1 sec 1 6 104 32 101 32 104 2 rate KIA IP 4 rate KIA B 16

1 The half life of a substance in a certain enzyme catalysed first order reaction is 138 s The time required for the concentration of the substance to fall from 1 28 mg L to 0 04 mg L 2 414 s 4 690 s 1 276 s 3 552 s

K for a zero order reaction is 2 x 10 mol L s If the concentration of the reactant after 25 s is 0 5 M the initial concentration must have been 1 0 5 M 3 12 5 M 2 1 25 M 4 1 0 M

CK0066 62 The rate constant for a second order reaction is 8 x 105 M min How long will it take a 1M solution to be reduced to 0 5 M 1 8 665 x 10 min 2 8 x 10 min 3 1 25 x 10 min 4 4 x 10 5 min CK0067 63 Agraph between t and concentration for nth order 68

3 K log K log 3 CK0079 80 73 The rate constant of a zero order reaction is 0 2 mol dm h If the concentration of the reactant after 30 minutes is 0 05 mol dm Then its initial concentration would be 1 6 05 mol dm 3 0 25 mol dm 2 0 15 mol dm 4 4 00 mol dm

3 50 kJ 4 30 kJ CK0109 100 Which of the following plot is in accordance with the arrhenius equation 1 log k 3 log k 4 2 log k 4 k 4

66 98 Pre Medical Chemistry The energy of activation of a forward reaction is 50 kCal The energy of activation of its backward reaction is 1 Equal to 50 kcal 2 Greater than 50 kCal 3 Less than 50 kCal 4 Either greater or less than 50 kCal CK0108

46 The rate constant of a first order reaction is 4 x 10 s At a reactant concentration of 0 02 M the rate of reaction would be 1 8 x 10 Ms 2 4 x 10 3 2 x 10 M s 4 4 x 10 Ms Ms CK

min min 13 CK0067 or nth order this nature es when i posed 50 espectively 68 CK0074 The following data were obtained at a certain temperature for the decomposition of ammonia p mm 50 100 1 2 3 64 1 82 The order of the reaction is 2 1 1 O 3 2 4 3 200 0 91 CK0075

CK0075 A reaction is found to have the rate constant xs 1 by what factor the rate is increased if initial concentration of reactant is tripled 1 3 2 9 3 x 4 Remains same

4 Unpredictable as rate constant is not given CK0065 61 The rate constant K for the reaction 2A B product was found to be 2 57 x 10 L mol s after 15 s 2 60 x 10 L mol s after 30 s and 2 55 x10 L mol s after 50 s The order of reaction is 1 2 2 3 3 Zero 4 1 CK0066

1 3 2 1 3 2 4 0 CKOOE 59 The rate constant for a reaction is 10 8 x 105 mol L s The reaction obeys 2 Zero order 1 First order 3 Second order 4 All are wrong CKOOE

55 From different sets of data of t 2 at different initial concentrations say a for a given reaction the txal is found to be constant The order of reaction is 1 0 2 1 3 2 4 3

72 The expression which gives th life of 1st order reaction is 1 K 2 303 log 2 303 K log 4 3 4 2 4 2 303 K 2 303 K log 3 log 4 4 1413 79 TI ch 1 3

1 Half life of a first order reaction is independer of initial concentration 2 Rate of reaction is constant for first order reactic 3 Unit of K for second order reaction mol 1 L s 1 4 Half life of zero order is proportional to initi

CK0061 7 Doubling the initial concentration of a reactant doubles of the reaction then order of the reaction is 2 2 1 3 3 1 4 0

CK0064 50 A substance A decomposes in solution following the first order kinetics flask I contains 1 L of 1M solution of A and flask II contains 100 ml of 0 6 M solution After 8 hr the concentration of A in flask I become 0 25 M what will be the time for concetration of A in flask II to become 0 3 M 1 0 4 hr 2 2 4 hr 3 4 0 hr 4 Unpredictable as rate constant is not given CKOOCE

Pre Medical Chemistry 61 39 For the reaction 2NO C 2NOCI the following mechanism has been proposed NO CI NOCI fast NOCI NO 2NOCI slow the rate law for the reaction is 1 Rate KINOPICLI KINO CI 2 2 Rate Rate

CK0057 1 For a given reaction of first order it takes 20 minute for the concentration to drop from 1 M to 0 6 M The time required for the concentration to drop from 0 6 M to 0 36 M will be 1 More than 20 min 2 Less than 20 min 3 Equal to 20 min

8 In a first order reaction the a la x was fou to be 8 after 10 minute The rate constant i 1 2 303x3log2 10 2 2 303 x 2log 3 10 3 10 x 2 303 x 2log3 4 10 x 2 303 x 3log2 6400

49 75 of a first order reaction was found to complete in 32 min When will 50 of the same reaction complete 1 24 min 3 8 min 2 16 min 4 4 min 56

In a reaction 2A products the concentration of A decreases from 0 5 mol L to 0 4 mol L in 10 minutes rate of reaction is 1 0 005 mol L min 2 0 002 mol L min 3 0 05 mol L min 4 0 02 mol L 1 min1

4 All of the above CK003 38 The reaction 2A B P follows the mechanis 2A A fast A B P slow The order of the reaction is 1 1 5 2 3 3 1 4 2 CK004

CK0026 25 For a reaction A B products the rate of the reaction was doubled when the concentration of A was doubled the rate was again doubled when the concentration of both A B were doubled the order of the reaction with respect to A B are 1 1 1 2 2 0 3 1 0 4 0 1 CK0027 31 31 F

The order of the over all reaction is 1 2 2 1 3 1 4 The rate for the reaction 4 Zero CK0034 RCI NaOH aq ROH NaCl is given by ratek RC The rate of the reaction is 1 Doubled on doubling the concentration of NaOH 2 Halved on reducing the concentration of RCI to half 3 Decreased on increasing the temperature of reaction 4 Unaffected by increasing the temperature of the reaction CK0035

al proposal aw of mass expression CK0025 Z W the 30 Consider the following reaction KCIO 6FeSO 3H SO KC1 3Fe SO 3H O Which of the statements regarding this reaction is incorrect 1 It is a complex reaction 2 It is a tenth order reaction 3 It is completed in several steps 4 Order of this reaction can be determined CAL VENETICE DES

CK0036 36 The rate law of the reaction A 2B product d P is given by dt excess the order of the reaction will be 3 2 1 Zero 2 1 4 3 K A B If A is taken in large

28 For a chemical reaction AB the rate of reaction doubles when the concentration of A is increased 8 times The order of reaction w r t A is 1 3 4 Zero 2 2 3 102

he A 26 31 Following mechanism has been proposed for a reaction 2A B D E C D me ler experimentally PSEUDO FIRST ORDER REACTION MECHANISM OF REACTION 27 CK0215 slow fast 1 3 KAP A B A C E The rate law expression for the reaction is KIA B 2 TK A B 4 r K AC CK0032 NODETABAS TARGET CHERRING

The rate of a first order reaction is 2 5 x 10 mol L 1 min at 0 25 M 1 concentration of reactant The half life in min of the reaction is O 69 3 O 43 5 O 76 6 38 7

ALLEN 32 The chemical reaction 20 30 proceeds follows 0 0 0 O 0 20 fast 0 0 slow The rate law expression should be 1 r KIO F 3 KIO 110 2 r KIOO 4 Inredictable

S The rate constant of the reaction A 2 B is 6 93 x10 s 1 If initial concentration of A is 2 M then the time in which B becomes 2 M is 10 s O 20 s O 10 min 20 min

Consider the following statements a Molecularity of a reaction can be zero b Order of a reaction can be fractional c Molecularity is not defined for a complex reaction Choose the incorrect statement s O a only O a and c only Ob and c only O a b and c