Chemical kinetics Questions and Answers

The half life of a radioactive minutes The time interval stages of its 33 and 67 decay is Question Type Single Correct Type 1 40 minutes 2 20 minutes element is 20 between the 3 30 minutes

The bromination of acetone that occurs in acid solution is represented by this equatio CH3 COCH3 aq Br2 aq CH3 COCH Br aq Br a These kinetic data were obtained for given reaction concentrations Initial concentrations M CH COCH 0 30 0 30 0 30 0 40 Br H 0 05 0 10 0 10 0 05 3 1X10 4 0 05 0 05 0 10 0 20 Initial rate disappearance of Br Ms 5 7X10 5 5 7X10 5 1 2X10 4 Based on these data the rate equation is a Rate k CH3COCH 3 H b Rate k CH COCH3 Br c Rate k CH3COCH3 Br H d Rate k CH3COCH3 Br H

Consider two reactions at 27 C 1 A B I order kinetics II X Y Zero order kinetics If both A X each having initial concentration 0 1M sa half life period Then find ratio of rate constants for I II K K In2 0 7 reactions

Hydrogenation of vegetable ghee at 25 C reduces pressure of H from 2 atom to 1 2 atom in 50 minute The rate of reaction in terms of molarity per second is 1 1 09 x 10 6 2 1 09 x 10 5 3 1 09 x 10 7 4 1 09 x 10 8

2 On doubling the initial concentrations of both A and B there is a change by a factor 8 in that rate of the reaction The rate of this reaction is given by 1 rate K A B 2 rate K A B 3 rate K A B 4 rate K A B

Q 7 Calculate the minimum amount of ethylene glycol molar mass 62g mol that must be added to 6 kg of water to prevent it from freezing at minus 0 3 c Given K for water 1 86K m

TYPE questions Fach question has 4 Consider the following statements a For zero order reaction t 2 is directly proportional to the initial concentration of the reactants b Inversion of cane sugar is an example of pseudo first order reaction c Decomposition of gaseous ammonia on a hot platinum surface is a zero order reaction at high pressure The correct statements are O a b only Read More Ob conly a c only

1 Following figure shows a graph in log 0K vs T where K is rate constant and T is temperature and an The straight line BC has slope intercept of 5 on Y axis Thus Ea the energy of activation is log K B 1 2 303 x 2 cal 1 2 303 1 T C 2 2 2 303 cal

From the following data for the reaction between A and B A B Initial rate at mol Lit sec mol Lit 2 5 10 5 0 10 1 0 10 mol Lit 3 0 10 5 6 0 10 6 0x10 5 300 K Overall order of this reaction is 3 5 0 10 4 0 10 1 6 10 2 Now select the correct statement s of the following 320 K 2 0 10 Units of rate constant of the above reaction is mol Lit sec Rate constant of this reaction at 320 K is 2 66 108 mol Lit sec Rate constant of this reaction at 320 K is 12 66x107 mol Lit sec Clear Re

A gaseous reaction A g B g C g shows increase in pressure from 100 mm te 120 mm in 5 minutes The rate of disappearance of A is 1 4 mm min 1 3 16 mm min 1 2 8 mm min 1 4 2 mm min 1

b Calculate the activation energy kJ mol and frequency factor for the reaction Express the final answers with 4 sig figs 5 pts en k 02331 4 605 Arrhenius Plot for Reaction A g 28 g AB 0 002907 0 003663 VT VK

The rate of a chemical reaction doubles for every 10 C rise of temperature If the temperature is raised by 50 C the rate of the reaction increases by about AIEEE 2011 A B C D 64 times 10 times 24 times 32 times

d 6 65 kJ mol The pyrolysis of an organic ester follows a first order process and its rate can be expressed as In K 78 09 42075 T Kalvin where K is given in the unit of min The time required for 25 percent reaction to complete at 227 C is a 50 mint b 125 mint c 250 mint d 500 mint

the initial For the reaction A B CD E reaction rate was measured for various initial concentrations of reactants The following data were collected Trial 23 A M 0 10 0 10 0 20 0 20 B C M M 0 10 0 10 0 10 0 30 0 10 0 10 0 10 0 20 Initial rate M s 3 0x10 5 9 0x10 1 2x104 1 2x10 4

46 t constant confirms the first order reaction If a t constant confirms that the order of reaction is a initial concentration of reactant 1 zero 2 first 3 second 4 third Which of following is correct formula for given polymer 47 46 47 a t a 1 3 fra

What is the activation energy for a reaction if its rate doubles when the temperature is raised from 20 C to 35 C R 8 314 J mol K 1 342 kJ mol 1 2 269 kJ mol 1 3 34 7 kJ mol 1 4 15 1 kJ mol 1

The rate constant the activation energy and the Arrhenius parameter of a chemical reaction at 25 C are 3 5 x 10 5s 1 110 5 kJ mol 1 and 6 0 x 10 4 s 1 respectively The value of rate constant at T o is OPTIONS CLEAR SELECTION MARK FOR REVIEW OA 1 5 x 105 s 1 OB 2 0 x 1010 s 1 OC 6 0 x 1014 S 1

In the following gaseous reaction 2A 4B C The concentration of B was found to increase by 5 x 10 mol L in 10 seconds The rate of reaction is mol L s 1 5 x 10 2 4 x 10 mol L 3 1 25 x 10 mol L 4 20 10 mol L s 82 4 10 000 ohm cm eq 2A4B CB 105 10 mol Larat t aff 1 5 x 10 2 4 10 3 1 25 10 4 20 x 10 mol L mol LS mol Ls mol L s

Select the correct diagram for an endothermic reaction that proceeds through two steps with the second step is rate determining 1 PE 2 PE 3 PE 4 PE Reaction coordinate Reaction coordinate ALLEN Reaction coordinate M 89 Reaction coordinate Addition of catalyst during a chemical reaction 90 En eff qot ar af ferata va n Autres fam 1 PE 2 PE 3 PE 4 PE Reaction coordinate Reaction coordinate Reaction coordinate M Reaction coordinate fat merefte affenf M

For a first order reaction if the initial concentration of the reactant is 0 8 M and rate constant is 6 93 10 3 s 1 then the rate of the reaction after 100 s will be 1 4 x 10 M s 1 2 5 x 10 2 MS 1 2 8 10 M S 1 1 9 x 10 4 MS 1

1 8 endothermic reaction energy of activation is E anc enthalpy of reaction is AH both of these in kJ mol Minimum For an value of E will be a less than AH more than AH 17 b equal to AH d equal to zero

During the decomposition of H O2 to give oxygen 48 g 0 2 is formed per minute at a certain point of time The rate of formation c water at this point is 0 75 mol min 1 O 1 5 mol min O 2 25 mol min O 3 0 mol min 1

is provided S A No I E O mol mol mol L L 1 L 1 s 4 x 10 2 O 4x10 2 22 2 x 10 B Rate A 4x10 2 B 8x10 2 o D 8 x 10 No CLEAR SELECTION The correct rate law expression will be 2 OPTIONS MARK FOR REVIEW d B k dt d B dt 2x 10 4 x 10 d B dt K A 2x 10 d B 2 2 0 2 k A B 401 K A B

Time required for 99 completion is the time required for the completion of 90 reaction for first order reaction fill in the blank with appropriate option given below O two times Othree times Ofour times

Which among the following statement is not true for rate constant of a reaction Unit of rate constant depend upon the order of reaction b Rate constant depend upon the concentration of the reactants c Rate constant has a definite value at a particular temperature d Rate constant changes with temperature O O b O a C

in the case of a chemical reaction are 37 5 and 51 3 kJ mole respectively The reaction is OPTIONS CLEAR SELECTION MARK FOR REVIEW OA Endothermic OB Exothermic C Neither exothermic nor endothermic

when OPTIONS MARK FOR REVIEW CLEAR SELECTION OA Concentration of all reactants are unity B Concentration of all reactants and products are equal C Concentration of reactants and products do not change with time

Mechanism of a hypothetical reaction 2XY is given below X2 Y 1 X X X fast ii X Y2XY Y slowest iii X Y XY fast The overall order of the reaction will be a 1 b 2 c 0 d 1 5

the initial concentration of the reactant A is 4 mol L The time required for its concentration to change from 0 40 to 0 20 mol L 1 is OPTIONS CLEAR SELECTION OA 0 75 min OB 2 min MARK FOR REVIEW O C 12 min

Consider the reaction N g 3H g 2NH3 g The equality relationship between d NH3 dt and d H dt is 1 d NH3 dt 1 3 d H dt 2 d NH3 dt 2 3 d H dt 3 d NH3 dt 3 2 d H dt 4 d NH3 dt d H dt

A first order reaction has a rate constant of 2 303x10 s The time required S for 40 g of this reactant to reduce to 10 g will be Given that log10 2 0 3010 1 230 3 s 2 301 s 3 2000 s

During the kinetic Study of the reaction 2A B C D following results were obtaine Run A mol L B mol L 1 I 0 1 0 1 0 3 0 2 0 3 0 4 IV 0 4 0 1 Initial rate of formation of D mol L min 6 0x10 7 2x10 2 88x10 2 40X10 Based on the above data which one of the following is correct 1 rate K A B 2 rate K A B 3 rate K A B 4 rate K A B

t1 4 can be taken as the time taken for 3 4 concentration of reactant to drop to of its initial value If the rate constant for a first order reaction is k then t1 4 can be written as O 0 10 k 0 29 k 0 69 k 0 75 k

For s reaction activation energy Ea 0 and the rate constant at 200 K is 1 6 X 106s 1 The rate constant at 400K will be Given that gas constant R 8 314 J K mol 1 1 3 2 x 104 1 S 2 1 6 x 106 s 1 3 1 6 x 10 1 4 3 2 x 106 1

The reduction of NO gas by H gas as represented below 2NO 2H N 2H O takes place in the sequence of following steps I NO NO N 0 II N O H N O H O slow III N O H N H O fast The reduction follows the rate law d N dt K NO H If K 6 6x10 mol L min and K the rate constant of step ll be 3 0x10 mol L min the numerical value of the equilibrium for the step I is ax102 Find the value of a

Which of the following will react at the highest rate 1 1 mol of A and 1 mol of B in a 1 L vessel 2 2 mol of A and 2 mol of B in a 2 L vessel 3 3 mol of A and 3 mol of B in a 3 L vessel 4 All would react at the same rate

two reactions occur in different container at same temperature that are Reaction 1 P Q Rate constant K s1 Reaction II A B Rate constant K S 1 Both reactions start at the same time and it is found rate of reaction I is four times of rate of reaction ll at the start If half life of reaction Il is two times of half life of reaction 1 Then select the correct statement 1 Initial concentration of P is two times of initial concentration of A 2 Initial concentration of P is four times of initial concentration of A Initial concentration of A is two times of initial concentration of P 4 Initial concentration of A is four times of initial concentration of P Aakash Education no Limited Read Office Aak

For given hypothetical elementary parallel reaction K 2B A where K K 1 4 K 2 K2C nitially only 2 moles of A are present The total number of moles of A B and C at the completion of 50 of reaction O 2 3

A portion of helium gas in a vertical cylindrical container is in thermodynamic equilibrium with the surroundings The gas is confined by a movable heavy piston The piston is slowly elevated by a distance H from its equilibrium position and then kept in the elevated position long enough for the thermal equilibrium to be re established After that the container is insulated and then the piston is released After the piston comes to rest what is the new equilibrium position of the piston with respect to initial position a The piston ends up 0 4H above its initial position b The piston ends up 0 6H above its initial position c The piston ends at its initial position d The piston ends up 0 4H below its initial position

In an experiment to study the reaction A 2B C 2D the initial rate d A dt a t 0 was found to be 2 6 10 M s 1 What is the value of d B dt 1 2 6 x 10 3 1 3 x 10 at t 0 in M s 1 2 5 2 x 10 4 1 0 x 10 1

In this experiment you will quantitatively measure a reaction rate of S O2 with I in solution to produce 1 according to the following reaction slow S 0 21 1 2504 The color change is very sudden and dramatic when 2x10 mol of Iz is produced The time required to produce 2x10 mol of l can be measured accurately 1 Write the rate expression for the reaction 2 Write the rate law for the reaction

An amount of 20 Ci of 32P TR 14 3 d is injected into the bloodstream of a reference adult m 70 kg 32p is metabolized in such a way that 40 is uniformly distributed throughout the whole body where it is cleared with a biological half life of 19 d What is the effective half life of 32P in the total body O A 19 d OB OC 8 16 d 3 26 d O D 14 3 d

3 100 cm of 1 M CH3 COOH was mixed with 100cm of 2M CH3 OH to form an ester The change in the initial rate if each solution is diluted with equal volume of water would be Yez Gal 4 fac 1 M CH3 COOHT 100 cm 2MCH3OH 100cm uz en una gran a 0 5 times c 0 25 times erar del b 2 times d 4 times

8 In the following questions calculate the final volume of gas in Litre at the specified conditions assuming the temperature and mass remain constant Ans a 0 15 L b 1 25 10 L a V 200 cm p 600 mmHg and p2 800 mmHg b V 110 m p 750 mmHg and p2 660 mmHg

the C D If the rate expression is 1 2A B r K A B and if volume is reduced to rate of reaction will increase 1 27 times 2 9 times 3 8 times 3 the

For reaction 2B Which of the following is correct 1 Rate of disappearance of B is twice that of rate of disappearance of C Medorral 2 Rate of disappearance of A is twice that of rate of disappearance of C 3 Rate of appearance of C is twice that of rate of disappearance of A 4 All of these

4 347 s The rate of formation of a dimer in a second order dimerisation reaction is 9 1 x 10 mol L sat 0 01 mol L monomer concentration What will be the rate constant for the reaction 1 9 1 10 L mol s 2 9 1 10 L mol s 3 3x10 L mol 4 27 3 10 L mol s 67 4 347 facta fe ft facra fufen 0 01 mol L 9 1 x 10 mol L Dimer Monomer fuffer from 1 9 1 10 L mol s 2 9 1 10 L mols 3 3 10 L mol 4 27 3 10 L mol s facer chefch

a gle a x K A A 1 386 min C 16 min a x 1 If 0 tan 0 5 and OA 2 1 cm then the half life for this reaction is t min D B 4 min 2 min

he reaction 2N O 4NO O initial pressure is 500 atm and rate constant k is 1 3 38 10 after 10 min the final pressure of N O is 490 at n 250 atm 480 atm 420 atm

Mechanism of reaction 203 302 can be given as K 03 O O fast K 0 020 slow Which of the following is correct rate law K r K 03 0 r K 0 1 0 r K K 03 0 r K3K1 0 1 03 K