Chemical kinetics Questions and Answers

5 Mechanism of a hypothetical reaction X 2XY is given below i X X X fast ii X Y XY Y slow 2 iii X Y XY fast The overall order of the reaction will be 1 2 3 1 5 2 0 4 1 Y 2

x 10 5 4 1 6 x 10 6 25 Which of the following plot represent first order reaction r rate at time t and r is the initial rate a c 3 rate 60 10 k Slope 2 303 b 1 a b d 2 a c d 2 b time Concentration d in r 11 2 Concentration In ro time

Reaction 1 A Reaction 2 C D E 20 kJ Ea If the initial temperature is 400 K for both reaction and the rate constants are equal then find the ratio of Arrhenius factor A A for reaction 1 and 2 12 18 2 71 lowing B Ea 28 31 kJ 132

For the dec the rate law is given as di The order of the reaction when the pressure of NH inside the reaction vessel is very low will be Zeo 15 4 2 Inllowing species there is ou

der the llowing A g B s C g The following data is given for the decomposition of A into B and C at 300 K and the reaction follows first order kinetics Time min 205000 Vol of C mL 1025160 It is given that vapour pressure of B s is negligible In16 2 77 In15 2 70 Identify the correct statement Rate constant of the reaction is 0 0035 sec 1 Rate of formation of B and C will be equal Volume of C will be equal to volume of A at time 100 min Volume of C will never become equal to volume of A

24 Consider the following reaction at 25 C 2A B C where the initial concentration of A is 0 48 M Assuming that this reaction is second order in A calculate how long in seconds it would take for the concentration of A to reach 0 24 M if A is initially decomposing i e at t 0 at a rate of 4 0 x 10 mol L 5 1 1 2 x 10 2 2 1 2 x 10 3 1 4 x 10 5 4 1 6 x 10 6 C 2

k 10 In a reversible reaction A k of A and B area and b in moles per litre and the equilibrium concentrations are a x and b x respectively express x in terms of k k a and b 1 2 3 k a k b K k2 4 k a k b K K2 k a k b k k2 ka kab k k A pas X when dissolved B the initial concentration 10 3 heat evolved Then SIE GE a x entfer 1 2 3 k k k a k k a H k 8 4 k

4 6 9 x 10 Rate law of reaction H g Br g 2HBr g is r k H Br 2 Molecularity of reaction is 1 2 2 3 2 3 1 4 Not defined 3 0 69 4 6 9 x 10 52 fushan H Br g 2HBr fer f H Br f fuffo argi 1 2 2 3 2 3 1 4 ff

Sir Mam plz explain answer in very easy approach Sir Mam plz explain answer from the Lines of NCERT If 80 of a first order reaction was completed in 80 minutes then 50 of the same reaction would be completed in log 5 0 7 log 3 0 48 1 40 minutes 2 70 minutes 3 64 5 minutes 4 34 4 minutes

1 6 4 43 fffe 2 7 9 3 9 6 ia ad fhda effe 4 11 6 vifaa i COCI g CO g Cl g ii CH g 2S g CS g 2H S g iii CO g C s 2CO g iv 2H g CO g CH OH g v CaCO3 s CaO s CO g vi 4NH g 50 g 4NO g 6H O g 2 3 1 1 3 5

A chemical process occurring in two steps is plotted as 2 1 Endothermic 2 2 Energy if n 3 A B The correct statement is Progress of Reaction A B 2 Exothermic X A B 3 Exothermic X X A B 4 Endothermic AB A B X fast X AB slow X slow AB fast X slow AB fast X fast

The following plot is drawn for a first order reaction A 2B B concentration 2 0 M 1 2 M 45 time min What is the half life period of the reaction as per the graphical data A 0 56 min B 0 84 min C 1 86 min

Rate of Reaction Factors Affecting the Reaction Rate 1 For the reaction N O5 2NO Given and 1 0 02 2 d N O5 dt d NO dt K N O5 K N O5 d 0 K N O5 dt The relation between K K and K3 is 1 2K K 4K3 3 2K 4K K 2 K K K3 4 K 2K 3K3

5 60 9875327541 par BEGINNER S BOX 3 The units of solubility product of silver chromate Ag CrO will be 1 mol L 2 mol L 3 mol L 4 mol L

1 Rate k A B 2 Rate k A B 3 Rate k A B 4 Rate k A B 0 For a reaction scheme A k Bk C if the rate of formation of B is set to be zero then 1 the concentration of B is given by k 1 A 2 k k A 3 k k A 4 k k A 1 The given plots represent the variation of the concentration of a reactant R with time for two different reactions i and ii The respective 2 4 3 8 4 1 THE Cons of ar diffe The depe volu

For the reaction mechanism A M KAM K 1 AM A k A M A Derive the rate law of the reaction using steady state approximation B Derive the rate law using pre equilibrium approximation C Under what conditions would the two methods have the

9 For following reactions A 700 K 500 X Product Product A Is was found that the E is decreased by 30 kJ mol in the presence of catalyst If the rate remains un the activation energy for catalysed reaction is Assume per exponential factor is same 1 75 kJ mol 2 105 kJ mol 3 135 kJ mol 4 198 kJ mol The maior product 7 obtained in the following reaction scheme is

1 At low temperatures the rate law for the reaction CO g NO2 g CO2 g NO g is Rate K CO NO2 Don t ask my bad NO Work out the rate law for each of the following mechanisms show all your work and then circle the one that is consistent with the rate law determined above Circle i ii iii i CO NO2 CO2 NO slow ii NO2 NO O equil O CO CO2 slow iii 2 NO2 2 NO O2 equil CO 02 CO2 O slow O NO NO2 fast

The rate constant of a first order reaction is 15 10 b 7 57 s a 34 07 s d 15 s to 3 0 g c 10 10 s Half life period of a first order reaction is 10 min What percentage of the reaction will be completed in 100 min a 25 b 50 c 99 9 d 75 tatements is incorrect

2 Assume that the cooking of an egg is a first order process Assume further that it takes 3 minutes to half cook soft boil an egg at 100 C If the activation energy of the cooking of an egg is 75 kJ mole how long would it take to soft boil an egg at the top of Mt Everest where water boils at 80 C

3 8 Consider the following reaction A B C Experiment 1 2 3 Initial A 0 10 M 0 20 M 0 20 M Initial B 1 0 M 1 0 M 2 0 M The order of reaction with respect to A and B respectively are 2 2 0 0 2 3 2 1 12 2 4 Rate of Formation of C mis 2 1 10 3 8 4 10 3 8 4 10 3

At some temperature and under a pressure of 5 atm P C15 is 20 dissociated Calculate the pressure at which P C15 will be 30 dissociated temperature remaining the same A 1 685 atm B 0 192 atm

For a reaction N g 3H g rate of consumption of N will be 1 3 10 2 mol dm s 3 3x10 mol dm s 2NH3 g the rate of formation of NH3 was found to be 2 x 10 2 mol dm s The L 2 1 x 10 2 mol dm s 4 x10 mol dm s otion vessel is sudd

k 5 757 10 1 In a second order reaction both the reactants have equal initial concentration for 60 completion of reaction is 3000 second What will be the time taken for 20 of the reaction ka 1 Let a 1

For a reaction A Product graph of concentration of reactant versus time is given Concentration of reactant M 0 04 0 03 0 02 0 01 200 Time s The rate in Ms of reaction after 53 34 seconds

1 Preservative 2 Pheromones 3 Antioxidant 4 Detergent At what temperature will the molar kinetic energy of 0 3 mol of He be the same as that of 0 4 mol of argon at 400K 1 700K 2 500K 3 800K 4 400K Reaction A B C D follows rate law R K A B starting with 1 M of A and B What is time taken for concentration of A to become 0 1 M Given K 4 606 x 10 s 1 1000 s 2 1500 s 3 2000 s 4 5000 s

A solution has a 1 4 mole ratio of pentane to hexane The vapour pressure of the pure hydrocarbons at 20 C are 440 mmHg for pentane and 120 mmHg for hexane The mole fraction of pentane in the vapour phase would be 0 549 O 0 200 O 0 786

1 2 3 3 4 4 2 47 The given plots represent the variation of the concentration of a reactant R with time for two different reaction i and ii The respective order of the reactions are ii 1 1 0 In R 2 1 1 time R 3 0 1 time 4 0 2

1 For the reaction 2N O 4NO 0 The values of rate constant and rate of reaction are respectively 3x10 s and 2 4x10 mol L s concentration of N O in mol L will be 2 0 8 1 0 4 Hanife 3 1 2 4 0 6

At 27 C temperature following experimental observations are obtained for the reaction 2A B 3C Exp No 1 2 3 1 A 2 0 01 M 0 02 M 0 02 M The value of rate constant for reaction is 3 6 93 x 10 5 1 B Question Type Single Correct Type 6 93 x 10 4 1 0 01 M 0 01 M 0 02 M 3 46 x 10 45 1 Rate M sec 1 6 93 x 10 6 1 386 x 10 5 1 386 x 10 5

The rate constant for the first order reaction below is 0 0617 s A B 1st attempt l S

COH COH COCH 1 2 4 75 of the first order reaction completed in 32 min 50 of the reaction was completed in 1 24 min 2 8 min 3 16 min 4 4 min A diatomic gas belonging to group 15 combines with a halogen to form a trihalide which is fairly stabl

Mechanism X2 Y2 2XY is given below i X X X fast ii X Y XY Y slow iii X Y XY fast The overall order of the reaction will be of a hypothetical reaction 1 2 3 1 5 2 O 4 1

The rate of the reaction 2NO Cl 2NOCI is given by the rate equation rate k NO C1 the value of rate constant can be increased by 1 Increasing the concentration of NO 2 Increasing the concentration of the Cl 3 Increasing the temperature 4 all of these

A solution is a mixture of 0 05 M NaCl and 0 05 M Nal The concentration of iodide ion in the solution when AgCl just starts precipitating is equal to Ksp AgCl 1 x 10 10 M K AgI 4 x 10 6 M A 2 10 7 M B 2 x 10 M C 4 x 10 6 M D 8 x 10 15 M

For the reaction 3BrO BrO 2Br in alkaline aqueous solution the value of the d BrO dt second order rate constant in BrO in rate law for and as 10 M s The rate constant in M s when the rate law is written as d Br dt was found to be 0 06 is b then the value of a b 100 is d BrO dt is a

A 10 cm diameter disk is placed at the center and parallel to a 25 cm diameter hemisphere Designating the sphere as surface 1 the disk as surface 2 and a large surrounding room as surface 3 calculate all the shape factors

For parallel reaction all following first order kinetics k 3B k 8C k 3D at time 1 0 initial mole of A is 1 If overall half life of reaction is 15 days and kyky kj 4 2 1 then log2 0 3 213 514 Number of moles of C after 45 days are 2 Number of moles of B after 30 days are Total moles at the end of reaction are 3 36 28 Ratio of moles of B D at any time except t 0 is 4

Consider the following reaction mechanism A A 21 K 4 B 1 K 1 B C K K K and K I and I are intermediates Which of the following expression is correct d C k A dt A 9 d C K K 41 B 4 C K 4 dt d C

C D is an elementary 2 The reaction A 2B g g process In an experiment the initial partial pressure of A B and Bare P 0 60 atm and P 0 80 atm When P 0 20 atm the rate of reaction relative B to the initial rate is 1 1 24 32 a 1 16 b C d 1 48

Problem 7 1 The following were concentrations obtained for the formation of NH from N and H at equilibrium at 500K N 1 5 x 10 2M H 3 0 x10 2M and NH 1 2x10 2M Calculate equilibrium constant C a a h C

in concentration of species X and Y for the reaction X 3Y as a function of time the point of intersection of the two curves represents 1 5 2 2 13 4 3 4 4 Data insufficient to predict 11 14 PM Concentration Y Time

117 The variation of equivalent conductance of strong electrolyte with concentration is correctly shown in the figure 1 Acq 3 Aeg C 2 Aeq 4 Aeq C

11 2 If is 8 The equivalent conductance of NaCl at concentration C and at infinite dilution are and is given as 1 B C 3 B C 2 B C 0 4 B C JEE Main 2014 Single 1

The hydrolysis of methyl acetate in alkaline medium follows 2nd order rate law CH3COOC H5 OH CH3COO C H5OH ate k CH COOC H5 OH The value of k at 298 K is found to be 0 137 Lmol s If initial conc of each reactant is 0 05 M The time ta 5 ethyl acetate to be hydrolysed will be a 7 35 s b 74 s c 740 s d 7 4 min

2C1 0 g 2C1 g 50 g At a certain temperature it obeys this rate law rate 0 699 M CLOS Suppose a vessel contains Cl O at a concentration of 1 41 M Calculate the concentration of Cl O in the vessel 3 60 seconds later You may assum reaction is important Round your answer to 2 significant digits

32 Which of the following curves assures that ther obtained by carbon reduction is in the vapour state a AG AG b AG c 1 C CO AG C d T C CO T M MO T M MO C CO CO M M MO MO C

The equilibrium constant for the reaction H g S g H S g is 18 5 at 925 and 9 25 at 1000 respectively What is the enthalpy of the reaction 1 142 16 kJ mole 2 71 08 kJ mole 3 35 54 kJ mole 4 none of these

1 The forward rate constant for the elementary reversible gaseous reaction C H62CH3 is 1 57 x 103 s at 100 K What is the rate constant for the backward reaction at this temperature if 10 moles of CH and 10 moles of C H6 are present in a 10 litre vessel at equilibrium a 1 57 x 10 L mol s c 1 57 x 10 L mol s 1 b 1 57 x 100 L mol 8 1 d 1 57 x 107 L mol s

Using the given graph showing the concentration of reactants and products as a function of time for the reaction A3 3A The time t corresponds to 1 2 Question Type Single Correct Type t1 2 conc t1 3 t A A3 time