Physical Chemistry Questions

In a NaCl type crystal distance between Na and CI ion is 2 814 and the density of solid is 2 167 g cm3 then find out the value of Avogadro NA 2XM 4 x5 815 814 x 10 8 constant 1 6 05 x 1023d xa 3 12 10 x 1023 2 3 02 x 1023 4 9 6 x 1024

In the reaction VO Fe O3 FeO V 05 the eq wt of V O is equal to its OAM 1 Mol wt 2 Mol wt 8 3 Mol wt 6 4 None of these

Redox reactions play a pivotal role in chemistry and biology The values of standard redox potential E of two half cell reactions decide which way the reaction is expected to proceed A simple example is a Daniel cell in which zinc goes into solution and copper gets deposited For the cell Pt H 0 4 atm H pH 1 H pH 2 H 0 1 atm Pt The measured potential at 25 C is Given 2 303 RT F 0 06V log 2 0 3 A 0 1 V B 0 5 C 0 042 D 0 035

22 How many times does the electron go round the first Bohr s orbit of hydrogen in one second

0 A gaseous alkane was exploded with oxygen The volume of O for complete combustion to CO formed was in the ratio of 7 4 The molecular formula of alkane is 2 a CH4 c C3H6 b C H6 d C4H10

Two moles of gas A are mixed with two moles of gas B in a flask of volume 1 lit If at equilibrium 0 5 moles of A are obtained Then find out K for reaction 1 12 3 4 A g B g 2AB g 9 4 36

The resistance of 0 01 N solution of an electrolyte was found to be 200 ohm at 298 K using a conductivity cell of cell constant 1 5 cm The equivalent conductance of solution is A 750 mhocm eq B 75 mho cm eq C 750 mho cm eq D 75 mho cm eq of not

Which of the following is true about the charge acquired by p type semiconductor A B C D Positive Neutral Negative Depends on concentration of p impurity

The ratio of activities of two ratio nuclides X and Y in a mixture at time t 0 was found to be 4 1 After two hours the ratio of activities become 1 1 If the t1 2 of ratio nuclide X is 20 min then t 2 in minutes of ratio nuclide Y is

The graphs representing distribution of molecular speeds at 300 K for gases Cl and N are as shown in figure atomic mass N 14 Cl 35 5 fraction of molecules I II x molecular speed a I graph is for N and II is for Cl b II graph is for N and I is for Cl c either graph can be taken for N or Cl d information is not sufficient

ml of 0 1 M KC1 200 ml of 0 01 M NaNO3 and 500 mL of 0 1 M AgNO was mixed The molarity of K Ag C NO3 in the solution would be K 0 04 Ag 0 04 Na 0 002 CI 0 04 NO3 0 042 K 0 04 Na 0 002 NO3 0 0433 K 0 04 Ag 0 05 Na 0 0025 CI 0 05 NO3 0 0525 K1 0 05 INa 1 0 0025 NO 0 0525

2 0 9 L 3 2 0 L 4 9 0 L Q 11 If Ksp of CaF2 at 25 C is 1 7 x 10 10 the combination amongst the following which gives a precipitate of CaF is JEE MAIN online 2012 1 1 x 10 2 M Ca2 and 1 x 10 5 M F 3 1 x 10 3 M Ca2 and 1 x 10 5 M F 2 12 The pH of a 0 1 molar solution of the acid Hi AIEEE 2013 2 1 x 10 4 M Ca2 and 1 x 104 MF 4 1 x 10 2 M Ca2 and 1 x 10 3 M F

Latent heat of vaporisation of a liquid at 500 K and 1 atm pressure is 10 0 kCal mol What will be the change in internal energy of 3 mol of liquid at same temperature and pressure 1 13 0 kCal AV AH Ang RT 3 27 0 kCal X 3H O l 3H Ocg 2 13 0 kCal 31 n 3 4 27 0 kCal 3x10 3 X 2 3x10 g tooo Nool

In the reactions A s B g C g and D s E g F g total pressure at equilibrium are 80 atm and 40 atm respectively then ratio of their equilibrium constants is

4 Physical adsorption is inversely proportional to a Volume b Concentration c Temperature A

Tyndall effect is observed only when i the diameter of the dispersed particles is not much smaller than the wavelength of the light used ii the refractive indices of dispersed phase and dispersion medium differ greatly in magnitude iii the size of the particles is generally between 10 11 and 10 m in diameter iv the dispersed phase and dispersion medium can be seen separately in the system b i and iv a i and iii c ii and iii d i and ii

For conductivity extrapolation of o not possible by of a versus C curves to zero concentration 1 KCI 3 NaCl 2 NH OH 4 K SO4

22 Which of the following solution will have pH close to 1 0 A 100 ml of M 100 HCl 100 ml of M 10 NaOH B 55 ml of M 10 HCl 45 ml of M 10 NaOH C 10 ml of M 10 HCI 90 ml of M 10 NaOH D 75 ml of M 5 HCI 25 ml of M 5 NaOH

2 Given the standard electrode potentials K K 2 93V Ag Ag 0 80V Hg2 Hg 0 79V Mg2 Mg 2 37 V Cr Cr 0 74V Arrange these metals in their increasing order of reducing

A cell with two electrodes one of grey tin and the other of white tin both dipping in solution of NH SnCl showed zero e m f at 18 C What conclusion may be drawn from this 6 ROMOTIO a The e m f developed at the electrode solution phase boundary cancels the normal e m f els bisboate b Grey tin being non metallic ceases to provide a reversible electrode reaction c Electrode surface develops a protective layer and the cell develops a very large internal resistance C d The free energy change of the cell becomes zero

Number of peroxide linkage in CrO5 H SO5 H S O8 are respectively 1 2 1 2 2 2 2 2 3 1 1 1

4 If the hydrogen electrodes in two solutions of pH 3 and pH 6 are connected by a salt bridge the emf of the result ing cell is A 0 177 V C 0 052 V B 0 3 V D 0 104 V

L A solid A B has NaCl type close packed structure If the anion has a radius of 250 pm should be the ideal radius for the cation Can a cation C having a radius of 180 pm be slip into the tetrahedral site of the crystal A B Give reason for your answer

Based on Laws of chemical combination which of the following statement is correct 1 In compound A 1 00g nitrogen combines with 0 57g oxygen In compound B 2 00g nitrogen combines with 2 24g oxygen In compound C 3 00g nitrogen combines with 5 11g oxygen These results obey Law of multiple proportion 2 In the reaction Hydrogen g Oxygen g water vapour the ratio of volumes is 2 1 2 This illustrates Avagadro s law 3 Two samples of lead oxide were separately reduced to metallic lead by heating in a current of hydrogen The weight of lead from one oxide was half the weight of lead obtained from the other oxide The data illustrates Law of definite proportions 4 A sample of pure carbon dioxide irrespective of its source contains 27 27 carbon and 72 73 oxygen

When 6x10 5g of a protective colloid was added to 20 mL of a standard gold sol the precipitation of latter was just prevented on addition of 2 mL of 10 NaCl solution X The gold number of a protective colloid is 100 What is the value of x

50 For the following processes AH KJ Mol A B 2B C D y E B 3 C Z For 2A 3B 3D E AH will be 1 2z x 2y 3 z 2x 2y X 2 z 2x 3y 4 2 2x 3x

photon of wavelength 4x10 m strikes on metal surface the work function of the metal being 2 13 eV Calculate the energy of the photon eV i the kinetic energy of the emission and ii the velocity of the photoelectron GV 16020x10 29

al test At 88 C benzene has a vapour pressure of 900 torr and toluene has a vapour pressure of 360 torr What is the mole fraction of benzene in the mixture with toluene that will be boil 88 C at 1 atm pressure benzene toluene form an ideal solution FC

ILLUSTRATION 8 20 A solution of 3 0 x 10 kg of camphor C10H160 in 25 3 x 103 kg of chloroform boils at 61 3 C If the boiling point of chloroform is 61 0 C calculate K and AHvap of chloroform

A X3 Kp 1 08 x 10 23 sp Q 49 Determine the solubility of AgCl in 0 1 M BaCl Kp for AgCl 1 10 10 sp

9 0 1 g atom of radioactive isotope zXA half life 5 day is taken How many number of atoms will decay Roorkee 1988 during eleventh day DI 206

Aluminium oxide contains 52 90 aluminium and carbon dioxide contains 27 27 carbon Calculate the percentage of aluminium in aluminium carbide assuming that the law of reciprocal proportions is Ans 75 true

The highest electrical conducitivity of the following aqueous solution is of 1 0 1 M fluoroacetic acid 2 0 1 M difluoroacetic acid 4 0 1 M chloroacetic acid 3 0 1 M acetic acid

The solubility of K SO4 in water is 16 g at 50 C The minimum amount of water required to dissolve 4 g K SO4 is a 10 g b 25 g c 50 g d 75 g

What will occur if a block of copper metal is dropped into a beaker containing a solution of IM ZnSO 1 The copper metal will dissolve and zinc metal will be deposited 2 No reaction will occur JEE MAINS ONLINE 2016 3 The copper metal will dissolve with evolution of oxygen gas 4 The copper metal will dissolve with evolution of hydrogen gas

38 An aq solution of phenol is weakly acidic Ka of phenol at 298 K is 1x 10 10 The degree of dissociation of 0 05 M phenol in a 0 01 M sodium phenolate solution is 1 0 S 1 5 10 8 802 2 2x10 6 HOOOH 3 5 10 10 4 1 10 8

9 64 Cu half life 12 8 h decays by emission 38 emission 19 and electron capture 43 Write the decay products and calculate partial half lives for each of the decay processes IIT 2002

The heat of combustion of CH is 2878 kJ mot If the heats of formation of CO and H 0 a 393 5 kJ moland 285 8 kJ mol then the hea of formation of CH is 1 125 0 kJ mol 2 126 75 kJ mol 4 402 3 402 5 kJ mol

The mass of a non volatile solute of molar mass 40 g mol that should be dissolved in 114 g of octane to lower its vapour pressure by 20 is a 10 g c 9 8 g b 11 4 g d 12 8 g 2012

Which one of the following arrangements represents the correct order of solubilities of sparingly soluble salts Hg Cl Cr SO4 3 BaSO4 and CrCl respectively JEE MAIN Online 2013 1 1 K sp K sp 108 K 2 K sp sp 27 I K 3 K 3 K sp 108 27 K 3 sp 4 2 K K K sp 27 4 K sp 108 K sp 27 Ksp K sp 108 sp 4

asks are separately filled with the gases CO2 F2 NH3 and He at same room temperature and pressure The ratio of total number of atoms of these gases present in the different flasks would be 1 1 1 1 1 2 1 2 2 3 3 3 2 4 1

Anf of 348 3 318 4 168 8 146 0 90 8 58 5 187 9 217 8 Which of the following oxide can be converted to metal easily ZnO Cu O HgO PbO 1 ZnO 3 PbO 2 HgO 4 Cu O

The magnitude of standard reduction potentials of two metals X and Y are Y2 2e Y X2 2e X When two half cells of X and Y are connected to construct a galvanic cell electrons flow in the extern circuit from X to Y When X is connected to a standard SHE electrons flow in the external circuit fro X to SHE If a half cell X2 0 1M X is connected to another half cell Y2 1 0 M Y to construct galvanic cell at 25 C Calculate the EMF of cell 2 303 RT Given At 25 C F E 0 34V E 0 25V 0 06

Arrange the following in order of a Increasing oxidation no MnCl2 MnO2 Mn OH 3 KMnO 4 b Decreasing oxidation no HXO4 HXO3 HXO2 HXO c Increasing oxidation no 1 HI HIO 4 ICl

Uncertainty in position of a minute particle of m 25 g in space is 10 5m The uncertainty in its velo in ms is AIEEE 200 a 2 1x 10 34 c 2 1x 10 28 b 0 5x 10 34 d 0 5 x 10 23

9 H O restores the colour of old lead paintings blackened by the action of H S gas by 1 Converting PbO to Pb 2 Oxidising PbS to PbSO 3 Converting PbCO3 to Pb 4 Oxidising PbSO to PbSO

12 The EMF of the cell M Mn 0 01M H 1M H g 1 atm Pt at 25 C is 0 82V Calculate th valency of the metal if the standard oxidation potential of the metal is 0 76V 2 303 RT F Take M 0 06 at 25 C

How many metals are commercially reduced by Gold schmidt alumino thermite process from the given metals Na Pb Al Mn Cr Sn

If the percent yield for the following reaction is 65 0 how many grams of KCIO are needed to produce 42 0 g of O 2KCIO3 s 2KCl s 30 g B 107 g A 69 7 g C 165 g D 371 g

Of the following which of the statement s regarding Bohr theory is wrong n IS a Kinetic energy of an electron is half of the magnitude of its potential energy a b Kinetic energy of an electron is negative of total 90x1 2 energy of electron c Energy of electron decreases with increase in the value of the principal quantum number d The ionization energy of H atom in the first excited state is negative of one fourth of the energy of an electron in the ground state