Physical Chemistry Questions

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

Assuming the formation of an ideal solution determine the boiling point of a mixture containing 1560g benzene molar mass 78 and 1125g chlorobenzene molar mass 112 5 using the following against an external pressure of 1000 Torr Pressure 2200 1350 90 100 110 120 bonzono c 20 C chlorobenzene d 110 C

aluation 5 An aqueous solution of 2 non volatile solute exerts a pressure o 1 004 bar at the normal boiling point of the solvent What is the molecular mass of the solute a 41 35 g mol c 23 4 g mol 7 The reactivity of the compound 1 b 10 g mol d 20 8 g mol

15 If the concentration of OH ions is the reaction Fe OH 3 s Fe aq 3OH aq is decreased 3 3 1 by times then equilibrium concentration of Fe will 4 increase by a 16 times c 4 times 1 1 CBSE PMT 2008 b 64 times d 8 times constant of the 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

CK0094 87 According to the arrhenius equation a straight line is to be obtained by plotting the logarithm of the rate constant of chemical reaction log k against 95 1 T 2 log T 3 T 4 log CK0095

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

Hydrolysis of adenosine triphosphate ATP is used to drive biological reaction Which of following processes can be driven by hydrolysis of one mole of ATP molecules Biosynthesis of tripeptide 3 A peptide links with each link involving A G 17 kJ mol B C Biosynthesis of protein with 150 peptide links with each link formation involving A G 17 kJ mol Biosynthesis of 1 mole sucrose from glucose fructose with A G 23 kJ mol

117 A person requires 2870 kCal of energy to lead normal daily life If heat of combustion of cane sugar is 1349 kCalmol then his daily consumption of sugar is 1 728g 342g 3 2 0 728g 4 0 342g

Re AIPMT 2015 20 The rate constant of the reaction A B is 0 6 x 10 M sec If the concentration of A is 5 M then concentration of B after 20 min is 1 0 36 M 2 0 72 M 4 3 60 M 3 1 08 M

TD0068 53 For a reaction at 25 C enthalpy change AH and entropy change AS are 11 7 x 10 Jmol and 105 J mol K respectively The reaction is 1 Spontaneous 2 Non spontaneous 3 At equilibrium 4 Can t say anything

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

Which of the following is INCORRECT statement A B C D In adiabatic expansion of an ideal gas temperature of system always decrease In isothermal expansion of an ideal gas temperature of a gas always remains constant In a reversible adiabatic compression of an ideal gas change in entropy of system is zero In an irreversible adiabatic compression of an ideal gas change in entropy of system is

4 Either greater or less than 50 kCal CK0108 9 An exothermic reaction X Y has an activation energy 30 kJ mol If energy change AH during the reaction is 20 kJ then the activation energy for the reverse reaction is 1 10 kJ 3 50 kJ 2 20 kJ 4 30 kJ CK0109 10

6g urea is dissolved in 1kg solvent Value of T T will be K 2 kg K mol Solvent Vapour pressure Solid Solvent 1 0 2 C 2 0 2 C 3 0 1 C Solution T T Temperature K

79 The Gibbs free energy change of a reaction at 27 C is 26 kCal and its entropy change is 60 Cals K AH for the reaction is 1 44 kcals 3 34 kals 2 18 kCals 4 24 kcals TD0088

40 g NaOH i 2 is dissolved in 1L volatile solvent vapour pressure of this solution becomes equal to its solid phase at 300K What is the freezing point of pure solvent Density 1g mL kf 1 8 k kgmol 1 296 4 K 2 303 6 K 3 297 5 K 4 302 4 K

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

ctively the e reaction 4 41 2 TC0117 and carbon espectively noxide is HEAT OF COMBUSTION 111 According to equation CH 15 2 0 g 6CO g 3H O 0 AH 3264 4 kJ mol the energy evolved when 7 8 g benzene is burnt in air will be 1 163 22 kJ 2 32 64 kJ 3 3 264 kJ 4 326 4 kJ

1 E E 3 E E 2 E E 4 E 4E CK0088 1 At room temperature the reaction between NO and O to give NO is fast while that between CO and O is slow it is due to 1 CO is smaller in size than that of NO 2 CO is poisonous 3 The activation energy for the reaction 2NO O 2NO is less than 200 0 2C0 4 NO is poisonous AL KINETICS02 EXEP65

AIPMT Pre 2012 13 In a zero order reaction for every 10 rise of temperature the rate is doubled If the temperature is increased from 10 C to 100 C the rate of the reaction will become 1 64 times 3 256 times 2 128 times 4 512 times CK0135 19

10 One mole of nitrogen is mixed with 3 mole of hydrogen in a closed 3 litre vessel 20 of nitrogen is converted into NH 3 Then K for the N H NH3 is 3 2 2 NTSE 1994 11 a 0 36 litre mol b 0 46 litre mol c 0 5 litre mol 1 1 1 1 d 0 2 litre mol A characteristic feature of reversible reaction is that

16 Calculate the Gibb s energy change when I mole of NaCl is dissolved in water at 25 C Lattice energy of NaCl 777 8 KJ mol AS for dissolution 0 043 KJ mol and hydration energy of NaC1 774 1 KJ mol 1 9 114 KJ mol 3 5 4 KJ mol 2 11 4 KJ mol 1 4 1 5 KJ mol 1

83 An endothermic reaction A Bhave an activation 90 energy 15 kCal mol and the heat of the reaction is 5 kcal mol The activation energy of the reaction B A is 1 20 kCal mol 3 10 kCal mol 2 15 kcal mol 4 Zero CK0091

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

16 The heat evolved during the combustion of 112 litre of water gas at STP mixture of equal volume of H and CO is Given H g 1 2O g H O g AH 241 8 kJ CO g 1 2O g CO g AH 283 kJ 1 241 8 kJ 3 1312 kJ 2 283 kJ 4 1586 kJ 12

d none of the abo 12 Equilibrium constants K and K for the followin equilibria are related as CBSE PMT 2005 k NO g 102 g NO g O g 2NO2 g a K2 7 1 c K K NO g K 2NO g O g K2 45 1 1 K2 d K K 2 12

14 The dissociation equilibrium of a gas AB2 can be represented as 2AB2 g 2AB g B g The degree of dissociation is x and is small compared to 1 The expression relating the degree of dissociation x with equilibrium constant K and total pressure P is CBSE PMT 2008 a 2K P 1 3 b 2Kp P 2 c Kp P d 2Kp P

129 The heat of neutralization of HCI by NaOH is 135 55 9 kJ mol If the heat of neutralization of HCN by NaOH is 12 1 kJ mol The energy of dissociation of HCN is 1 43 8 kJ 2 68 11 2 43 8 kJ

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

3 Numerically equal to the heat of formation 4 1 and 3 both TC0135 120 The value of AH for the combustion of C s is 127 94 4 kCal The heat of formation of CO g is 1 49 5 kCal 2 94 4 kCal 3 188 0 kCal 4 More data required TC0136

252 Pre Medical Chemistry 115 The combustion of one mole of benzene takes place 121 at 298 K and 1 atm After combustion CO g and H O l are produced and 3267 0 kJ of heat is liberated Calculate the standard enthalpy of formation A H of benzene Standard enthalpies of formation of CO g and H O l are 393 5 kJ mol and 285 83 kJ mol respectively 1 48 51 kJ mol 2 48 51 kJ mol 122

95 For the reactions i H g Cl g 2HCl g xkJ ii H g Cl g 2HCI ykd Which one of the following statement is correct 1 x y 3 x y 2 x y 4 More data required TC0106

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

14 The enthalpy of formation for CH g CO g and H O at 25 C and 1 atm pressure are 52 394 and 286 kJ mole respectively The enthalpy of combustion of C H will be 1 1412 kJ mole 2 1412 kJ mole 3 142 2 kJ mole

94 The enthalpy of a reaction at 273 K is 3 57 kJ what will be the enthalpy of reaction at 373 K if 2 Zero AC zero 1 3 57 kJ 3 3 57 x 373 273 kJ 4 375 kJ 100 TH rea 1 3

AH for transition of carbon from diamond form to graphite form is 453 5 Cal This suggests that 1 Graphite is chemically different from diamond 2 Graphite is as stable as diamond 3 Graphite is more stable than diamond 4 Diamond is more stable than graphite

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

18 be of 112 Heat of combustion of CH C H C H and C H gases are 212 8 373 0 337 0 and 310 5 kCal respectively at the same temperature The best fuel among these gases is 1 CH 2 C H 3 C H 112 Hea 4 C H TC0125 113 Given standard enthalpy of formation of

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

AIPMT 2015 8 The activation energy of a reaction can be determined from the slope of which of the following graphs 2 In k v s In k 1 TV S T T 1

An aqueous solution of hydrochloric acid 1 obeys Raoult s law 2 Shows negative deviations from Raoult s law 3 Shows positive deviations from Raoult s law 4 Obeys Henry s law at all compositions

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