Physical Chemistry Questions

or Ax Ap Ax Av mass X h 4 iiFor other canonical conjugates of motion the equation for Heisenberg uncertainty principle can be modified Momentum mass x velocity h m x 4 velocity time AE X At 2 force x time Momentum x distance force x distance x time energy x time x time Apx Ax AE x At h 4 T iii Why an electron cannot For energy and time exist in the nucleus The 10 14 to 10 15 m Hence if photon of light stril seen with the help displayed in Fig 2 the impact changes According to which the position the wavelength of It shows that shor position But a ra energetic in natur electron the im direction of the electron changes Photons with lon less effect on th larger waveleng position of the e

54 If one atom of an element A weighs 6 644 x 10 23 g the number of gram atoms in 20 kg of it is b 20 01 x S 10 d 2000 a 500 c 1000 TO JE 11 55 The volume occupied by 1 mole atom of a diatomic gas STP is a 22 4 L b 11 2 L 5501 0 8 6

More Than One Option Correct ch of the following changes is are observed when ore is heated for calcinations A PbSO4 PbO PbSO4 B PbCO3 PbO C PbS D Fe O3 3H O Fe O3 hich of the following is a halide ore

WORKED OUT EXAMPLES EXAMPLE 14 1g of graphite is burnt in a bomb calorimeter in excess of oxygen at 298 K and I am pressure accom to the equation Cigr Ogg CO g During the reaction temperature rises from 298 K to 299 K If the heat capacity of bomb calorimeter is 20 7 kJ K N C E R T 20 K

18 Assertion Total number of octahedral voids present in unit cell of cubic 1 point close packing including the one that is present at the body centre is four Reason Besides the body centre there is one octahedral void present at the centre of each of the six faces of the unit cell and eac of which is shared between two adjacent unit cells B O D

If A is more reactive than B then which of the following is true i A will replace B from a salt of B ii B will replace A fro m a salt of A iii Both can displace each other from their salts iv Both cannot di splace each other from their salts

In electric deflection 1 a rays 3 D ray field which have maximum angle of Assume all have same velocity 2 H rays 4 All have equal highest

1 Which of the following is correct for following graph B A C V P Composition 1 At point C composition in vapour phase will be same as in liquid phase 2 Boiling point of azeotropes will be more than A and B on 3 At point C both component having same boiling 10SM point 4 All of these

Identify the incorrect statement among following 1 CH CH 10 CH NH is not a surfactant 2 Surfactants are positively adsorbed at interfaces between two phases and they lower interfacial tension 3 Quaternary ammonium salts cannot act as surfactants 4 Surfactants can be neutral positive or negative in charge

3 3 K Rb Cs K E 4 Cs Rb K K E Maximum electron in 3rd shell having m 2 will be 1 2 2 O 3 12 4 24 What about degeneracy of 2p orbitals in a magnetic field 1 No degenerate orbital 2 Three degenerate orbital 3 Two degenerate orbital 4 Cannot be stated any thing about degenracy 9 10

8 Which of the following statements is not true 1P 1 Paramagnetic substances are weakly attracted by magnetic field O ii Ferromagnetic substances cannot be magnetised permanently O iii The domains in antiferromagnetic substances are oppositely oriented with respect to each other iv Pairing of electrons cancels their magnetic moment in the diamagnetic substa

correct choice 1 Which of the following statement is not true about amorphous solids O 1 On heating they may become crystalline at certain temperature O ii They may become crystalline on keeping for long time O iii Amorphous solids can be moulded by heating iv They are anisotropic in nature

6 Which of the following point defects are shown by AgBr s crystals A Schottky defect B Frenkel defect C Metal excess defect D Metal deficiency defect 1 A and B ii C and D O iii A and C iv B and D

The conductivities at infinite dilution of NH CI NaOH and NaCl are 130 218 120 ohm 1cm eq 1 If N solution of NH OH equivalent conductance of 100 is 10 then degree of dissociation of NH OH at this dilution is 1 0 005 3 0 01 2 0 043 4 0 02

c In the case of bigger particles having considerable mass the value of uncertainty product is negligible Uncertainty principle is important only in the case of smaller moving particles like electrons For an electron of mass m 9 1 x 10 2 g the product of uncertainty is quite large Ax Av h 4 m 6 626 10 27 X 28 4 x 3 14 x 9 1 x 107 0 57 erg sec per gram approximately Note i For solving mathematical problems the expression of uncertainty principle is generally written as h Ax Ap 4 Incident Fig 2 26 Chang momentum an photon of light strike seen with the help of displayed in Fig 2 2 the impact changes i

8 x g of NaCl is added into 100 ml of H O to prepare y molar solution 10 ml of its sample taken in separate test tube The molarity of the sample taken in test tube will be 1 10y M 2 W 2 5y MomeH 8 4 Oy M

For a reaction AP the plots of A and P with time at temperatures T and T are given below 10 A mol L S T T B C AH 0 AS 0 10 AGO 0 AH 0 P mol L AGO 0 AS 0 5 Time Time If T T the correct statement s is are Assume AH and AS are independent of temperature and ratio T of nk at T to In K at T then 2 Here H S G and K are T FA enthalpy entropy Gibbs energy and equilibrium constant respectively T T 2

48 Equimolal solutions of NaCl and BaCl are prepared in water If the freezing point of BaCl solution is 3 C the freezing point of aqueous NaCl solution will be 1 3 C 2 2 C 3 1 C 4 4 C

Q 55 A mineral of iron contains an oxide containing 72 36 iron by mass and has a density of 5 2 g cc Its unit cell is cubic with edge length of 839 pm The total number of atoms ions present in each unit cell is Fe 56 0 16

tron be accelerated with a y may be given as charge on the particle lomb On vii we get vii with the help of de Broglie concept of wave nature of electron Consider an electron moving in a circular orbit around nucleus The wave train would be associated with the circular orbit as shown in Fig 2 23 If the two ends of the electron wave meet to give a regular series of crests and troughs the electron wave is said to be in phase i e the circumference of Bohrs orbit is equal to whole number multiple of the wavelength of the electron wave So 7 28 10 10 m or 10 39 m be measured as it waves but the Thus mation the following is its de Broglie ller is its de Broglie s independent of the sendent of charge From de Broglie equation or cable to microscopic en partiell molecule etc and has e wavelength is too which is difficult to oving electron and a travelling with the i e 2tr n N h mu 2tr 11 Wave in phase Z h mur n MU 2tr n Angular momentum n h 2 v velocity of electron and r radii of the orbit h 2 t 9 N Wave out of phase experiment confirm that When an zinc s with produced scintillation striking like a the our 2 21 Evidence to Support Particle and Wave Nature of Electron ii w was prove a D subjected filament the elect nickel ca Fig 2 23 This proves that the de Broglie and Bohr concepts are in perfect agreement with each other Note The calculations show that the velocity of de Broglie waves associated with a moving particle is greater than the velocity with which the particle moves Therefore it was difficult to understand as to how the de Broglie waves are associated with a particle A plausible solution to this problem is that a moving particle is associated with a wave packet rather than a wave Sou alec

d composition 2 An element crystallises in fcc lattice having edge length 350 pm Maximum radius of the atom which can be placed in the interstitial site without distorting the structure is a 58 55 pm b 117 pm d 83 pm c 51 23 pm

2 51 Given that the temperature coefficient for the saponification of ethyl acetate by NaOH is 1 75 The activation energy for the saponifiocation of ethyl acetate is K cal mol

c 2 648 g d 5 295 g 1 Which of the following contains the greatest number atoms a 1 0 g of butane C H 0 b 1 0 g of nitrogen N c 1 0 g of silver Ag d 1 0 g of water H O

An aqueous solution of sodium acetate is subjected to Kolbe s electrolysis to prepare ethane If a current of 5 A is passed for 1930 sec then total volume of all gases collected STP is 2 24 L 4 48 L 5 6 L 11 2 L

4 5 g of aluminium at mass 27 amu is deposited at cathode from Al solution by a certain quantity of electric charge The volume of hydrogen produced at STP from H ions in solution by the same quantity of electric charge will be a 44 8 L 2005 6 11 2L b 22 4L d 5 6L

Half life for the zero order reaction A g X g B g C g and half life for the first order reaction Y g are equal If completions time for the zero order reaction is 13 86 min then calculate the rate constant in hr for the reaction X g Y g

4 The wavelength of second Balmer line in Hydrogen spectrum is 600 nm The wavelength for its third line in Lyman series is a 800 nm c 400 nm 016 b 120 nm d 200 nm WB JEE

24 The mass of beryllium 9 is 9 012182 g mol The mass of a proton is 1 007825 g mol The mass of a neutron is 1 008665 g mol Calculate the binding energy of Be 9 c 3 00 x 108 m s a 2 93 x 10 J mol b 8 12 x 10 1 J mol c 3 08 x 10 2 J mol d 5 54 x 10 2 J mol e 5 62 x 10 2 J mol

9 For the cell Pt H HC Cu Cu Ecell can be decreased by 1 4 1 increasing pressure of H gas 2 increasing Cu2 in cathodic compartme F 3 Increasing the pH in anodic half cell 4 Addition of H SO in anodic half cell

Consider the given table Metals Threshold frequency x10 s A 5 2 B 3 8 C 4 6 D 5 8 Photoelectrons ejected from which metal surface will have highest kinetic energy on irradiating with light of frequency 8 6 x 10 5 s O C OB O A

1 30 In a solid AB having the NaCl structure A atoms occupy the corners of the cubic unit cell If all the face centered atoms along one of the axes are removed then the resultant stoichiometry of the solid is a AB c A3B4 b A B d A B3

5 d What is the percent dissociation of N O4 At some temperature and under a pressure of 4 atm PCl is 10 dissociated Calculate pressure at which PCls will be 20 dissociated temperature remaining same PCls dissociates according to the reaction Pl POLY

by 2 The Activation energy is lowered 8 314 kJ mol for the catalysed reaction The ratio of the rate of the catalysed reaction to that of the uncatalysed reaction at 500K is Given e 7 38 1 7 38 2 14 5 3 8 37 4 4 83

5 The solution used to re acidify the basic solution was 6 M HCI The stockroom made 3 L of this solution so that all the lab sections had enough After looking up the molarity of concentrated HCI explain how this solution was made Please include calculations in your answer for full credit

ex combustion of octane C8H 8 in air 79 N 21 O 1 C H18 problems What is concentration of CO in exhaust How much CO released per year per typical car typical fuel data Poctane 703 g L MWoctane 114 g mol typical car data fuel economy 30 mpg 3 785 L gal 15 05

If one litre of sea water which weighs 1100 g contains 6 6 x 10 g of dissolved oxygen then the concentration of oxygen in ppm is 2 5 ppm 6 ppm 6 8 ppm 12 ppm

the unit cell of a mineral has cubic close packed ccp array of oxygen atoms with m fraction of octahedr moles occupied by aluminium ions and n fraction of tetrahedral holes occupied by magnesium ions m and JEE Adv 2015 Paper 1 espectively are 1 1 28 1 1 A C B 1 D 4 1 1 48

4 KBr KlFe A metal carbonate 0 5 kg gives 0 28 kg of its oxide on heating Hence the equivalent weight of metal is 1 20 g eq 2 40 g eq 3 25 g eq 4 30 g eq

the same orifice if CO was kept under the same conditions 7 78 hrs Determine the percentage of a gas mixture CH4 H2 CO2 if after the combustion of 15 mL o it with 85 mL of air the volume reduced to 83 2 mL and the total contents of CO in mixture was found to 10 8 mL H 28 CH4 35 CO2 37

If the amount of dissociation is 0 5 the value of K for the reaction N O NO NO will be 3 1 equal to the pressure of the system 2 3 3 8 3 L of the pressure of the system of the pressure of the system of the pressure of the system

Find the 5th coordination number in CsCl structure Also find the distance of the atom from cs I am asking this question 2nd time Please don t give the wrong answer Find the distan ce from cs

Instructions Look at the example of methane in the chart below Notice how the carbon atom in methane forms four single covalent bonds with hydrogen atoms It s molecular formula is CH Next fill in the missing molecular formulas structures names and uses in the chart below Refer to pages 674 676 in your textbook and the following website for additional help https hzorganichemistry wordpress com uses of alkene The of Akm Horganichemistry World Press 16 June 2011 Web 15 Dec 2016 Molecular Formula CHA C H HICI Structure HIC H C H HIC HIC Name H H Methane Ethane SUMMER SES Propane Uses Pentane Gas used for cooking Lighter and camping fuel Use in petrol Used in petrol

Avogadros Law given Starting Volume width in nm 5 0 nm effect on Volume constant Starting Temp K 300K effect on temp 300k Starting Pressure atm 23 3 atm Effect on pressure atm constant 23 3 Number of Gas Particles 100 heavy 100 H 200H This is Gas Laws PhET simulation

Calculate the internal energy and enthalpy changes resulting if air changes from an initial state of 5 C and 10bar where its molar volume is 2 312 x10 m mol to a final state of 60 C and 1 bar Assume also that air remains a gas for which PV T is constant and that C 20 785 and C 29 100 Jmol K

7 A liquid mixture of 50 mole n butane and 50 mole n pentane at 60 C and total pressure of 2600 mm Hg At equilibrium find the composition of both the liquid and vapor phases What fraction of the original liquid was vaporized If the mixture is heated further to 80 C what is the resulting pressure

8 The mass of carbon anode consumed giving only carbon dioxide in the production of 270 kg of aluminium metal from bauxite by the Hall process is Atomic Mass Al 27 1 270 kg 3 90 kg 2 540 kg 4 180 kg R

ii For gas molecules h mX Vrms where k Boltzmann h 3mkT constant 2 c In SS th certain ving 9 1

e poin group 101 101 sy y grou If C5 C and Oy are the generators of a point group write down the point group and give an example of a molecule with the structure 2 NN F 1 11

18 The pH of pure water at 25 C is 7 If heated to boil then 1 pH will decrease and water will become acidic 2 pH will increase and water will become basic 3 pH will decrease but water will remain neutral 4 pH will remain 7 2015 16

la A real gas is placed in a container if intermolec attraction are supposed to disappear suddenly ther 1 The pressure decreases 2 The pressure increases 3 The pressure remain unchanged 4 The gas collapsest H