Physical Chemistry Questions

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

Ionic solid AB s M wt 50 crystallise in NaCl s type structure if edge length of unit cell is 1 x 10 7 cm then calculate density of AB s in 3 gm ml if it contain 100 3 schottky defect NA 6 102

A and B will result The correct statement s is are ST The distance between two nearest octahedral voids of a cubic closed packing of atoms with radius r is 2r B The distance between two tetrahedral voids of a cubic closest packing of atoms with radius r is 6 r at the body diagonal axis C The distance between tetrahedral and octahedral void is 1 5 r where r is the radius of atom forming the closest cubic packing D The distance between the surfaces of atoms in fcc arrangment along an edge is 2 2 1 ven properties

If Aut Au is 1 69 V and Au Au is 1 40 V E then Au Au will be Question Type Single Correct Type 1 E 2 3 0 19 V 2 945 V 1 255 V

The standard electrode potential of Zn Ag and Cu electrodes are 0 76 V 0 80 V and 0 34 V respectively then 1 Ag can oxidise Zn and Cu 2 Ag can reduce Zn and Cu 3 Zn can reduce Ag and Cu 4 Cu can oxidise Zn and Ag FC0017

48 Which of the following compounds will give methyl orange by the reaction with diazonium salt of sodium p amino benzene sulphonate 1 Aniline 2 N N Dimethyl aniline 4 m bromophenol 3 m nitro aniline 49 The relation between K and Ke for the reaction 4 g B g C g 2D g is DY P PIRTT JK DT

46 Choose the correctly matched pair from the codes given below A CH CH COCH B CH C NH 47 1 2 octanone 2 Trimethyl amine 3 Acrolein 4 Vinyl acetylene C CH CH CN D CH CH C CH 1 1 and 4 2 2 and 3 3 2 and 4 4 1 and 3 The current needed to reduce 26 6 9 of nitrobenzene to aniline in acidic medium is

An ideal gas can be expanded from an initial state to a certain volume through two different processes A PV2 K B P KV2 where K is a positive constant Then choose the correct option from the following 1 Final temperature in A will be greater than in B 2 Final temperature in B will be greater than in A 3 Work done by the gas in both the processes would be equal 4 Total heat given to the gas in A is greater than in B

0 What is the time required in seconds for depositing all the silver present in 125 ml of 1 M AgNO solution by passing a current of 241 25 A 1F 96500 C a 10 sec b 50 sec c 1000 sec d 100 sec

Which one of these statements about strong acids is true Select one O a The conjugate base of a strong acid is itself a strong base O b Strong acids produce solutions with a higher pH than weak acids O c Strong acids react completely with water to become 100 ionized Od Strong acids are very concentrated acids e All strong acids have H atoms bonded to electronegative oxygen atoms

Ex 1 One mole of an ideal gas expands isothermally and reversibly at 25 from a volume of 10 litres to a volume of 20 litres What is the change in entropy of the gas ii How much work is done by the gas

Which of the following statements is incorrect a One gram atom of carbon contains Avogadro s number of atoms b One mole of oxygen gas contains Avogadro s number of molecules c One mole of hydrogen gas contains Avogadro s number of atoms d One mole of electrons stands for 6 02 10 electrons

8 If the rate of a reaction at 50 C is 2 6 10 3 mol L s 1 then what will be rate of reaction at 80 C Given that the temperature coefficient is 3 a 7 02 10 c 7 8 x 10 3 b 7 025 x 10 d None of these

What is the threshold energy of reaction RP in represented diagram all energy in Kcal mol 1 1 12 Kcal mol 2 14 Kcal mol 3 50 Kcal mol 4 70 Kcal mol R C HEREHEHE

17 Half life t and completion time T of the zero orden reaction are K 0 001 mol litre sec and a 1 M a 500 min 750 min b 500 sec 750 sec c 500 sec 1000 sec d None of these

13 An aqueous solution of a compound AB freezes at 0 48 C At this temperature AB behaves as a Non electrolyte The same solution boils at 100 26 C at a P of 1 atm for water k kb 0 37 we can conclude that compound AB at the boiling point of solution a Behaves as a non electrolyte b Ionises to the extent of 50 c Behaves as a strong electrolyte d Dissociates in solution

32 The order of a reaction A reagent is reacted in half an hour three quarters in one product in which half the hour and seven eighth in one and half hours is a 2 b 1 c Zero d 1 32 A 103

0 5 mole each of two ideal gases A Cv m R R and B Cv m 3R are taken in a container 2 5 and expanded reversibly and adiabatically during this process temperature of gaseous mixture decreased from 350 K to 250 K Find AH in cal mol for the process a 100 R b 137 5 R c 375 R d None of these

30 Specific conductance of 0 1 M NaCl solution is 1 01 10 cm Its molar conductance in 2 cm mol is a 1 01 x 102 b 1 01 10 c 1 01 x 104 d 1 01 31 Limiting molar conductivity of NaBr is 38

15 The mass of 350 cm of a diatomic gas at 273 K at 2 atmospheres pressure is one gram Calculate the ma of one atom of the gas 10 jou 16 How 00 nd molecules of phosphorus are present in 124 g of phosphorus P

5 Suppose a galvanic cell employs the following half reactions Ni aq 2 Ni s E Cr aq 3 Cr s E c Ni2 0 25 V Cr3 0 74 V Calculate the cell potential when Ni 4 87 104 M and Cr 2 48 10 M

4 A 0 5 L reaction vessel which is equipped with a movable piston is filled completely with a 1 M aqueous solution of H O The H O decomposes to H O and O g in a first order process with half life of 10 hrs at 300 k As H O decomposes the piston moves up against constant external pressure of 1 atm The net work done from the start of sixth hour till the end of 10 hours is nearly a 100 J b 120 J c 130 J d 150 J

10 Two reactions R R have identical pre exponential factors Activation energy of R exceeds that of R by 10 kJ mol Ifk k are the rate constants for reactions R R respectively at 300 K then In k k is equal to R 8 314 J mol k a 12 c 4 b 6 d 8 18 A de m re a C 19 W f

If a solute X undergoes dimerisation and solute Y undergoes trimerisation the minimum values of the van t Hoff factor for X and Y will be respectively 0 33 and 0 5 1 33 and 1 5 0 5 and 0 33 0 2 and 0 67

Which of the following statement is are CORRECT A cation is smaller than an anion if they are isoelectronic Out of second period anion fluoride ion is large in size Both Mn and Co are paramagnetic Generally metallic radius of an element X is higher than its covalent radius

The following half reactions are provided for 40 each metal Cr aq 3 e Cr s E red 0 744 V Zn aq 2 e Zn s E red 0 763 V Which of the following is the half reaction a that takes place at the anode 0 of 0 25 points earned 3 attempts remaining What is the standard cell potential for this b cell 0 of 0 25 points earned 3 attempts remaining Write the balanced equation for the overall C reaction in acidic solution 0 of 0 25 points earned 3 attempts remaining

c 52 m S 35 Which of the following expressions correctly represents the equivalent conductance at infinite dilution of Al2 SO4 3 Given that A 8 are the mol A13 3A so A 3 A A1 so equivalent conductances at infinite dilution of the respective ions a 2A A13 and A so b 2A 8 2 6 4 A A13 A Al3 So 1 A so

338 U is the element of III d B group It undergoes decay as follows 238 U 92 A A will be of III B group B A will be of IB group C B will be of II A alkaline earth metal group BBC which of the following statements is are correct D C is the isotope of 338 U 92

c P R was 36 AgNO3 aq was adde measured The plot of conductance A versus the gradually and the conductivity of the solution volume of AgNO3 is a A Volume P Volume R b A d A b Q d S 1 Volume Q Volume S ion

9 Discounting economic considerations which of the following would be the best to shrinkle an icy road in quantities proportion to their respective formula weights a NaCl b CaCl c CuSO4 5H O d Al SO4 3

75 titute A 0 1 M 2 Cu aq B 0 1 M NH aq S P M In which of the following compartment Blue colour of Cu NH3 4 2 will be observed first 1 A compartment 2 B compartment 3 Blue colour will be observed at same time in both compartment 4 None of these compartment shows blue colour

B H are longer but stronger 2 I II and IV 1 I II and III 6 The addition of NH CI to 0 1 M acetic acid will cause bond 1 Increase in its pH value 2 Decrease in its pH value 3 No change in its pH value 4 Unpredictable change in its pH value norm 3 I II III and IV onds 4 Only II

40 How much will the reduction potential of a hydrogen electrode change when its solution initially at pH 0 is neutralised to pH 7 a Increase by 0 059 V b Decrease by 0 059 V c Increase by 0 41 V d Decrease by 0 41 V

3 A living cell contains a solution which is isotonic with 0 2 M glucose solution What osmotic pressure develops when the cell is placed in 0 05 M BaCl solution at 300 K a 1 23 atm b 6 15 atm c 3 69 atm d None of these

is the normal molecular mass and a is the 2 If M normal degree of ionization of K Fe CN then the abnormal molecular mass of complex is a M 1 3a b M 1 2a normal normal c M 1 d None of these normal

6 A current of 1 40 ampere is passed through 500ml of 0 180 M solution of zinc sulphate for 200 seconds What will be the molarity of Zn ions after deposition of Zinc a 0 154 M b 0 177 M d 0 180 M c 2 M

3 Conductivity of a saturated solution of a sparingly soluble salt AB at 298 K is 1 85 x 10 5 Sm Solubility product of the salt AB at 298 K is Given A AB 140 104 Sm mol a 5 7 x 10 2 b 1 32 x 10 12 c 7 5 x 10 12 d 1 74

The numerical values of rate constants are same for first second and third order reactions Which one is true at a definite moment for rate of these three reactions if concentration of reactants is same and less than 1 M Question Type Single Correct Type 1 2 3 4 r r2 3 r1 12 13 r1 12 13 None of these

7 The volume of water K 18 6 k molal in 100 g solvent required to dissolve 3 g of urea to produce a depression of 0 186 C in freezing point is a 1 L b 200 ml c 500 ml d 300 ml

29 Calculate molar conductivity of 0 15 M solution of KCI at 298 K if its conductivity is 0 0152 S cm a 124 2 cm mol b 204 2 cm mol c 101 2 cm mol d 300 2 cm mol

The vapour pressure of a solution of liquid A and liquid B is 600 torr The mole fraction of component A in liquid phase is 0 7 The vapour pressure of pure A and B are respectively Question Type Single Correct Type 1 2 3 4 300 torr 130 torr 1300 torr 130 torr 300 torr 1300 torr 300 torr 300 torr

38 V ml of an aqueous urea solution having osmotic pressure equal to 2 4 atm is mixed with V ml of another aqueous urea solution having osmotic pressure equal to 4 6 atm at if resulting same temperature What will be value of V solution after mixing has osmotic pressure equal to 2 95 atm a 1 c 2 In ak V b 1 5 d 3

Which of the following is correct for the reaction 3X X3 a represents degree of association Question Type Single Correct Type 1 2 3 4 3 2 1 i 2 3 1 i a 2 3 1 1 a 3 1 i

6 If all the four compounds were sold at the same price which would be cheapest for preparing an antifreeze solution for a car radiator a CH OH c C H OH b C H OH d C H OH

When 0 16 g of glucose was burnt in a bomb calorimeter the temperature rose by 4 deg Calculate the calorimeter constant water equivalent of the calorimeter given that AH 2 8 x 106 J mol 1 molar enthalpy of combustion Molar mass of glucose 180 mol 1 5 73 x 10 J deg 2 7 53 x 10 J deg 3 6 22 x 10 J deg 4 3 57 10 J deg X

From which solution 2 faraday electrical charge will deposit 1 gram atom weight at cathode Auce 1 Auric chloride 2 Silver nitrate 3 Cuprous chloride Ag No cuce

A 40 0 mL sample of sulfuric acid is titrated to a neutral end point by the addition of 15 6 mL of a 0 250 M potassium hydroxide solution 4 Write the balanced formula equation for this reaction i What is the molarity of the sulfuric acid solution in this question

37 A solution containing 12 5 g of non electrolyte substance in 185 g of water shows boiling point elevation of 0 80 K Calculate the molar mass of a substance k 0 52 k kg mol a 53 06 g mol b 25 3 g mol c 16 08 g mol d 43 92 g mol 38 10 solution of urea is isotonic with

For the reaction 2NO H2N2O H2O The values of dp dt was found to be 1 5 Torr sec for a pressure of 359 Torr of NO and 0 25 Torr sec for a pressure of 152 Torr the pressure of H2 being constant On the other hand when the pressure of NO was kept constant dp dt was 1 6 Torr sec for a hydrogen pressure of 289 Torr and 0 79 Torr sec for a pressure of 147 Torr Determine the order of the reaction 2 Points a overall order 3 for constant H2 pressure order 2 for constant NO pressure order 1 b overall order 3 for constant H2 pressure order 1 for constant NO pressure order 2 c overall order 2 for constant H2 pressure order 2 for constant NO pressure order 0 d overall order 2 for constant H2 pressure order 0 for constant NO pressure order 2 overall order 2 for constant H2 pressure order 1 for constant NO pressure order 1