Physical Chemistry Questions

When 36 8g N O4 g is introduced into a 1 0 litre flask at 27 C The following equilibriur 2NO g K 0 1642 atm reaction occurs N O4 g Calculate K of the equilibrium reaction What are the number of moles of N O4 and NO at equilibrium What is the total gas pressure in the flask at equilibrium What is the percent dissociation of N O

In presence of fluoride ion Mn2 can be titrated with MnO4 both reactants being converted to a complex of Mn III in presence of F ions A 0 545g of sample containing Mn 304 was dissolved and all manganese was converted to Mn2 The titration in presence of fluoride ion consumed 31 1 mL of KMnO4 that was 0 117 N against oxalate a Write balanced chemical equation for the titration assuming that the complex is MnF4 b What was the of Mn 304 in sample

9 Which of the following will be the strongest bond a F O c N H b d 0 Cl H

40 The data for the reaction A B C is Exp A o B i 0 012 0 035 ii 0 024 0 070 iii 0 024 0 035 iv 0 01200 0 070 The rate law corresponds to the above data is 1 Rate k A B 2 Rate K A B 3 Rate k B 4 Rate k B 4 Initial rate 30 10 0 80 0 10 0 80

2 The rate constant for a first order reaction is 4 606 x 10 s 1 The time required to reduce 2 0 g of the reactant to 0 2 g is 1 100 s 1220 693 2 200 s 3 500 s 4 1000 s 1007 jo J 4606X1 103x2 4606 2x1 7

53 At a certain temperature and total pressure of K nots 1 atm A vapours contains 20 by volume of A atoms A g 2A g The Kp of reaction is 1 5 x 10 3 5 x 10 3 2 2 x 10 3 4 4 x 10 4

The correct order of ionic radii of the followin species is XXX 1 Se Br 0 F 2 1 Se 0 Br F X 3 Se Br F 0 X

4g H and 127g I are mixed heated in 10 lit closed vessel until equilibrium is reached If the equilibrium concentration of HI is 0 05 M total number of moles present at equili brium is 1 3 25 2 1 75 3 2 25 4 2 5

74 The wavelength of the radiation emitted when in hydrogen atom electron falls from infinity to stationary state 1 would be Rydberg constant 1 097 x 107 m 1 91 nm 2 9 1 x 10 8 nm 3 406 nm 4 192 nm

4 100 ml of 1 M KMnO4 oxidized 100 ml of H O in acidic medium when MnO is reduced to Mn volume of same KMnO4 required to oxidize 100 ml of H O in neutral medium when MnO is reduced to MnO2 will be A 100 3 ml B 500 3 ml C 300 5 ml D 100 ml

44 The percentage of void space of a metallic element crystallising in a ABCABC type lattice pattern is 1 24 2 26 3 34 4 74

69 The first emission line of hydrogen atomic spectrum in the Balmer series appears at R Rydberg constant 1 3 5R 36 7R 1 cm 144 cm 1 2 3R T cm 9R 4 cm 1 400

8 Kinetic data for hydrolysis of a 0 3 M solution of ethyl acetate in presence of HCI as catalyst is given in the following table A constant volume of reaction mixture is taken at different time and titrated against the same standard alkali solution at different time ime min 0 10 Vol of alkali solution ml 25 00 28 00 If the rate law is given as rate k Ester H where H is a catalyst find the rate in M min of ester hydrolysis in a solution which is 0 1 M each in ester ethyl ethyl acetate and acid 5 HCI In 2 4 0 225 A 4 5 10 4 C 4 5x10 6 t 40 00 B 4 5 10 5 D 4 5 10 7

Calculate maximum number of identical A segment X of cellulose obtained on partial hydrolysis has molecular mass 1476 gm On complete acidic hydrolysis mass of the product obtained is 1620 gm Find out the number of glycosidic linkage s present in segment X

Measuring Zeta potential is useful in determining which property of colloidal solution Viscosity 1 2 3 4 Solubility Stability of the colloidal particles Size of the colloidal particles

d is not 161 Consider the argon atom For how many electrons does this atom have m 17 d 2 a 1 b 6 c 4

A freshly prepared Fe OH precipitate is peptized by adding FeCl solution The charge on the colloidal particles is due to preferential adsorption of 1 Cl ions 3 OH ions 2 Fe ions 4 None

Solubility of AgCl in water 0 01 M CaCl 0 01 M NaCl and 0 05 M AgNO are S S2 S3 and SA respectively then a S S S3 S4 c S S S3 S4 b S S3 S SA d S S3 S4 S

Try Yourself 1 Conductivity of 0 12 M CUSO solution at 298 K is 1 8 x 10 2 S cm 1 Calculate its equivale conductivity

8 How many g of dibasic acid mol wt 200 should be present in 100 ml of its aqueous solution to give 2003 decinormal strength a 1 g 10g b 2 g d 20 g

20 Decomposition of a non volatile solute A into another non volatile solute B and C when dissolved in water follow first order kinetics as A 2B C When one mole of A is dissolved in 180 g of water and left for decomposition vapour pres sure after 12 hours was found to be 20 69 mm of Hg Determine V P of the solution after 30 hours Assume constant temperature through out to be 27 C and V P of pure water at 27 C is 24 mm of Hg

For a given exothermic reaction K and K are the equilibrium constants at temperatures T and T2 respectively Assuming that heat of reaction is constant in temperature range between T and T it is readily observed that 1 2 1 K K p 3 K K 2 Kp Kp 1 4 K

The dissociation pressure of silver oxide at 4450C is 207 atm Calculate DGo for the formation of 1 mole Ag2OC metal and oxygen at this temperature log 207 2 315 Report your answer in Kcal and round of the value to nearest integer

a total pressure of I atm The system N O4 2 NO maintained in a closed vessel at 60 C a pressure of 5 atm 2 average i e observed molecular weight of 69 calculate K At what pressure at the same temperature would the observed molecular weight be 230 3

The conductivity of a saturated solution of CaF at 25 C is 6x 10S cm1 The conductivity of pure water is 2 10 S cm If for Ca2 and F ions are 72 and 64 S cm mol then K of CaF is m A 4 x 10 10 B 3 2 x 10 14 C 9 8 x 10 14 D 9 10 10

09 An increase in the concentration of th reactants of a reaction leads to change in ten 1 1 len activation energy 2 heat of reaction 3 threshold energy 4 collision frequency

7 Find the concentration of H after mixing 20 ml 0 1M CH COOH and 10 ml 0 1 M NaOH Given K for CH COOH 1 7 x 10 5 302 a 3 1 1 7 x 10 5 2 3 4 x10 5 3 3 4 x 10 6 4 1 7 x 10 4

When 100 mL of IM HCl was mixed with 100 mL of 1 0 M NaOH in an isolated beaker at constant pressure a temperature increase of 5 7 C was measured for the beaker and its contents expt 1 Because the enthalpy of neutralisation of a strong acid with a strong base is constant 57 0 kJ mot this experiment could be used to measure the calorimeter constant In a second experiment Expt 2 100 mL of 2M acetic acid K 2 10 5 was mixed with 100 mL of 1M NaOH under identical condition to Expt 1 where a temperature rise of 5 6 C was measured Consider heat capacity of all solutions as 4 2 J gm K and density of all solutions as 1 gm mL Enthalpy of dissociation in kJ mot of acetic acid obtained in the Expt 2 is A 1 B 10 C 24 5 D 51 4

2 37 Find the conversion factor between the S I work using and the C G S units of work dimensional analysis

x100 100 50 10 Weight of N CO3 0 9031 g of a mixture of NaCl and KCI on treatment with H SO4 gave 1 0784 g of a m of Na SO4 and K SO4 Calculate percentage composition of the original mixture

0 The time t 2 1 wha ase 3 times rd and win time period for and t are time completion of two first order reactions If the half lives are in the ratio 10 3 then the ratio of t and t will be 1 1 23 2 0 81 3 0 11 4 2 70

An open vessel containing air is heated from 300K to 400K The fraction of air originally present which goes out of it is a 3 4 c 2 3 b 1 4 d 1 8

6 A detergent C12H25SO Na solution becomes a colloidal sol at a concentration of 10 3 M On an 100 average 1013 colloidal particles are present in 1 mm The average number of ions which are contained by one colloidal particle micelle is Given N 6 x 10 11

An increase in the concentration of the reactants of a reaction leads to change in activation energy heat of reaction 1 2 3 4 threshold energy collision frequency

The difference between elevated boiling point and depressed freezing point of an aqueous solution is 102 C The molality of the solution if it contains non volatile and non electrolyte solute will be 2 1 K Kb 3 K K 3 102 2 K K 3 4 K K

The ratio of second coordination number of Nat in NaCl to first coordination number of Cst in CsCl will be 1 12 8 2 8 8 3 12 4 4 8 12

Lithium has a BCC structure Its density is 530 kg m 3 and its atomic mass is 6 94 g mol Calculate the edge length of a unit cell of Lithium metal NA 6 02 x 1023 mol 2X6 94 1 154 pm 2 352 pm 3 527 pm 6 02 x 1023x 13 88 4 264 pm

A solution of palmitic acid in benzene contains 4 24g of acid per litre When this solution is dropped on water surface benzene gets evaporated and palmitic acid forms a unimolecular film on surface If we wish to cover an area of 500 cm with unimolecular film what volume of solution should be used The area covered by one palmitic acid molecule may be taken as 021 nm2 Mol wt of palmitic acid is 256 2

4 A sample supposed to be pure CaCO3 is used to standardise a solution of HCl The substance really was a mixture of MgCO3 and BaCO3 but the standardisation of HCl was accurate Find the percentage of BaCO3 and MgCO3 in mixture

13 An electron beam can undergo diffraction by crystals Through what potential should a beam of electrons be accelerated so that its wavelength is equal to 1 6 1 58 90 V 3 45 35 V 2 85 75 V 4 105 31 V

a NaOH CH COOH b HCI NH 3 41 What indicator should be used for the titration of 0 10 M KH BO with 0 10 M HCI K H BO 7 2 x 10 10 log 702 0 441 cid form of the indicator is red the basic form The acid

CH g 20 g CO g 2H O A H 170 8 kJ mol 1 Which of the following statements is not true 1 At equilibrium the concentrations of CO g and H O l are not equal 2 The equilibrium constant for the reaction is given by Kp CO CH410 3 Addition of CH4 g or O g at equilibrium will cause a shift to the right 1 Th

3 Which of the following reactions defines AH a C diamond O g CO g 640 to gian 1 b H g F g HF g wollon od no ed mot to tood c N g 3H g 2NH3 g Lo all aure tolygos to noted to rese d CO g 0 g CO g

75 If metal m crystallises in bcc structure and has radius 1 86 A then the nearest neighbour distance and edge length will be respectively 1 3 72 A 5 26 A 3 72 3 72 4 3 A 2 0 93 5 26 0 93 A 4 3

What is the effect of the reduction of the volume of the system for the equilibrium 2C s O g 2CO g Page nova A The equilibrium will be shifted to the left by the increased pressure caused by the reduction in volume B The equilibrium will be shifted to the right by the decreased pressure caused by the reduction in volume C The equilibrium will be shifted to the left by the increased pressure caused by the increase in volume D The equilibrium will be shifted to the right by the increased pressure caused by the reduction in volume

H g 1 2 O2 g K s H O 1 aq H O l AH 68 kcal KOH aq 1 2 H KOH s aq KOH aq AH 48 kcal AH 14 kcal From the above data the standard heat of formation of KOH is kcal is a 68 48 14 c 68 48 14 b 68 48 14 d 68 48 14

4 Zn rod is placed in 100 mL of 1M CuSO solution so that molarity of Cu2 changes to 0 7 M The molarity of SO2 at this stage will be 4 1 0 8 M 2 1 M 3 0 7 M 4 1 8 M

De job wit Ecell 0 59 V at or the cell reaction V at T 298 K 17 149 If the rate constant for a first order reaction is k the time t required for the completion of 99 of the reaction is given by 1 t 0 693 k 69 2 d 1386 2 3 4 t 6 909 k t 4 606 k t 2 303 k is

A solution of 500 mL of 0 2 M KOH and 500 mL of 0 2 M HCl is mixed and stirred the rise in temperature is T The experiment is repeated using 250 mL each of solution the temperature rise is T Which of the following is true a T T T b T 2T c T 4T d T 9T sidient

An electron in hydrogen atom falls from sixth excited state to first excited state Total possible lines emitted in the visible region are 2 15 4 21 1 Zero 3 5