Physical Chemistry Questions

5 According to Kohlrausch law the limiting value of molar conductivity of an electrolyte A B is 1 2 A 200 A BO 1 A 2 3 2200 BO 2 20 A 2 BO 4 2200 BO A 200

Following data is obtained for aqueous solution of NaCl at 25 C conc M A ohm m mol Identify the correct statement s regarding the solution at 25 C A The value of m is 0 017 ohm m mol B The value of Am for 0 16 M NaCl solution is 0 0162 ohm m mol C The conductivity of 0 04 M NaCl solution is 0 664 ohmm when the conductivity of neglected 0 25 1 00 0 016 0 015 Conductivity of NaCl solution increases on dilution b

Moles of K SO4 to be dissolved in 12 moles of H water to lower its vapour pressure by 10 mm at a temperature at which vapour pressure of pure water is 50 mmHg is A 3 mol C 1 mol B 2 mol D 0 5 mol

Consider the following redox reaction H O AX BY HA YO BX unbalanced It is also known that oxidation number of X is 2 and neither X nor water is involved in the redox process In compound BY B is cation and consider its oxidation number 4 Answer the following questions based on the information given Select the incorrect option The element A is undergoing reduction The element B is undergoing reduction The element B is undergoing oxidation The element Y is undergoing oxidation

A 4 log 2 B 4 log 2 C 10 log 2 D 10 log 2 Ka for HCN is 5 x 10 10 For maintaining a constant pH of 9 the volume of 5 M KCN solution require be added to 10 mL of 2 M HCN solution is A 4 mL B 8 mL 2MB C 2 mL D 10 mL

The first IE and second IE ionization enthalpies KJ mol 3 elements A B and C are given below A B C IE 403 549 1142 Identify the element which is likely to be i A non metal IE2 2640 1060 2080 ii An alkali metal iii An alkaline earth metal

107 For the half cell OH Ope OH O 2H 2e E 1 30 V At pH 2 the electrode potential is 1 1 36 V 2 1 30 V 3 1 42 V 4 1 20 V

1 Al OH 2 Zn OH 3 Both together 4 None at all A colourless liquid A b p 184 C is sparingly soluble in warm water to which it gives feebly alkaline On treating with NaNO and dil HC in the cold solution it yields a solution which reacts with an alkaline solution of B naphthol to give an orange yellow precipitate Compound A is 1 C H N CI 2 C H NHNH 3 n C H NH 4 C H NH

a 1 b 2 c 3 d 4 B When sulphur is heated at 900 K S is converted to S What will be the equilibrium constant for the reaction if initial pressure of 1 atm falls by 25 at equilibrium a 0 75 atm c 25 0 atm b 2 55 atm d 1 33 atm 26 In b

Thermal stability of BaCO3 CaCO and MgCO is 1 BaCO CaCO MgCO 3 CaCO MgCO BaCO In metal carbonyls there is 1 No z bond between CO and metal atom 2 BaCO MgCO CaCO 4 MgCO CaCO BaCO

Potassium crystallizes in a body centred cubic lattice with edge length a 5 0A Then choose the correct statements in given option The number of nearest neighbour to any K atom is 8 The number of next nearest neighbour to any K atom is 6 Distance between nearest neighbours is 4 33 A Distance between next nearest neighbours is 5 0

1 dien 2 tri n 3 en 4 dmg Arrange the following compounds in order of increasing dipole moment Increasing dipole moment I Toluene II III o dichlorobenzene m dichlorobenzene IV p dichlorobenzene 3 IV I III II 1 I IV II III 2 IV I II III 4 IV II I III Which of the following electrolutoe will be most effective in the coagulation of gold co

In a compound A atoms are at FCC lattice positions B atoms are in all tetrahedral voids and C atoms are in all octahedral voids of this lattice Assume B and C are of appropriate size so that there is no distortion in FCC lattice Find correct statement s Empirical formula of the compound is AB C In this compound B atoms will be touching the C atoms If atomic masses of A B and C are 20 30 and 40 respectively then mass of unit cell is 480 amu If radius of A atoms is 200 pm edge length of unit cell is 4 2

Alejandra just finished making her hydrogen calibration curve Her data is best described by the following equation y 127 4 ln r 715 23 If she observed a line in the helium spectrum that had a scale reading of 2 9 what wavelength would this correspond to If Carmen adds zeros to your answer do not worry It will be graded correctly

Suppose you need to prepare 117 3 mL of a 0 434 M aqueous solution of NaCl What mass in grams of NaCl do you need to use to make the solution Type answer

The equivalent conductance of monobasic acid at infinite dilution is 438 ohm cm eq If the resistivity of the solution containing 15g of acid Molecular weight 49 in 1L is 18 5 ohm cm What is the degree of dissociation of acid A 45 9 C 60 4 B 40 2 D 50 7

Study the data you collected for Trials 1 and 2 When the amplitude increases what happens to the wavelength O The wavelength increases O The wavelength decreases O The wavelength stays the same

Problem 7 1 The following were concentrations obtained for the formation of NH from N and H at equilibrium at 500K N 1 5 x 10 2M H 3 0 x10 2M and NH 1 2x10 2M Calculate equilibrium constant C a a h C

9 If one mole of an ideal gas C p m 5 R Ris expanded isothermally at 300 until it s volume is tripled then change in entropy of gas is a zero b infinity 5 R ln 3 d R ln 3 2 In previous problem if expansion is carried out freely Pext 0 then AS is b infinity a zero c R ln 3 d None When one mole of an ideal gas in

The basicity of hydrides of group 15 decreases in the order A NH3 AsH3 SbH3 BiH3 PH3 B C D NH3 PH3 AsH3 SbH3 BiH3 NH3 SbH3 AsH3 BiH3 PH3 BiH SbH AsH3 PH3NH

4 A buffer solution made up of BOH and BCI of total molarity 0 29 M has pH 9 6 and Kb 1 8 Concentration of salt and base respectively is A 0 09 M and 0 2 M C 0 1 M and 0 19 M B 0 2 M and 0 09 M D 0 19 M and 0 1 M

3 4 In a 10 litre box 2 5 mole hydroiodic acid is taken After equilibrium 2H1 H 1 the concentration of HI is found to be 0 1moll The concentration of H at equilibrium in mol L is 4 7 5 10 1 2 4 2 0 15 3 1 5

a 278 7 C b 278 7 K 78 AS for freezing of 10 g of H O l enthalpy of fusion is 80 cal g at 0 C and 1 atm is d 12 25 J K a 12 25 J K c 2 93 J K b 0 244 J K 79 Chloroform has AH vaporization 29 2 kJ mol and boils at 61 2 C What is the value m

The V Ps of two pure liquids A B at t C are 75 and 21mm Hg resp The two when mixed form an ideal solution What is the mole ratio A B in which the two be mixed to get a solution whose V P at t C is 39mm Hg 1 2 3 2 5 3 3 2 1 4 1 2 at the same temperature when 1g of B is dissolved

Holtz had given two equation and are known as Gibbs Helmholtz equation One equation can be expressed in terms of change in free energy AG and enthalpy AH while other can be expressed in terms of change in internal energy AE and work function AW AG AH T d AG dT da000 1 AW AW AE T d 2 dt V Where T is temperature equation 1 is obtained at constant pressure while equation B is obtained at constant volume system It is observed that for the reaction N g 3H g 2NH g Free energy change at 25 C is 33 kJ while at 35 C is 28 kJ which are at a constant pressure 5 What would be the difference between enthalpy change at 25 C and 35 C for a given reaction B 5 kJ C 3 kJ D zero A 4 kJ 6 What would be the free energy change at 30 C A 30 5 kJ B 33 kJ C 28 kJ D 30 5 kJ Internal energy change at 25 C is E while at 35 C is E then 7 A E E B E EFE D

An ideal gaseous sample at initial state i Po Vo T is allowed to expand to volume 2V using two different process in the first process the equation of process is PV K and in second process the equation of the process is PV K Then A Work done in first process will be greater than work in second process magnitude wise B The order of values of work done can not be compared unless we know the value of K and K C Value of work done magnitude in second process is greater in above expansion irrespective of the value of K and K D 1st process is not possible

The bond dissociation energies for Ch 12 and IC are 242 3 151 and 211 3kJ mol respectively The enthalpy of sublimation of iodine is 62 8 kJ mol What is the standard enthalpy of formation of ICI g 1 211 3kJ mol 2 14 6 kJ mol 3 16 8 kJ mol 4 33 5 kJ mol

a The heat of reaction A H for the formation of NH3 according to the reaction N 3H 2NH3 at 27 C was found to be 91 94 kJ What will be AH at 50 C The average molar heat capacities at constant pressure and between 27 C and 50 C for N H2 and NH3 are 28 45 28 32 and 37 07 J respectively

Freezing point of 0 2 M KCN solution is 0 7 C On adding 0 1 mole of Hg CN to one litre of the 0 2 M KCN solution the freezing point of the solution becomes 0 53 C due to complete conversion of Hg CN into complex ion Hg CN 2 by the reaction Hg CN mCN Hg CN What is the value of m m 2

20 The incorrect statement is a the spin only magnetic moments of Fe H O and Cr H O 612 are nearly similar the gemstone ruby has Cr ions occupying the octahedral sites of beryl the color of CoCl NH3 2 is violet as it absorbs the yellow light desitida bisa d the Jang si moment spin only Ni NH3 4 H O JOT magnetic is 2 83 B M 11 of gives a

Problem 36 For 10 minutes each at 27 C from two identical holes nitrogen an an unknown gas are leaked into a common vessel of 3 litre capacity The resulting pressure is 4 18 bar and the mixture contains 0 4 mol of nitrogen What is the molar mass of the unknown gas 300

How many kj of heat will be evolved in making 22 4 L at STP 1 00 mol of H S from Fes and dilute hydrochloric acid The enthalpies of formation of FeS s H aq Fe2 aq CI aq H S g are 95 4 0 87 9 167 0 20 6 kcal mol respectively 180 1 kl mol 180 1 kg mol 13 1 kcal mol 13 1 kg mol

ncorrect statement regarding product of reaction H Br 1 eq Kinetic controlled product is a secondary bromide whereas thermodynamically controlled product is a tertiary bromid Kinetic controlled product is a secondary bromide whereas thermodynamically controlled product is a primary bromi Both kinetic thermodynamic controlled product is secondary bromide Both kinetic thermodynamic controlled product is a tertiary bromide

The enthalpy of combustion of carbor hydrogen and sucrose are 393 5 286 2 an 5644 2 kJ mol respectively Calculate th enthalpy of formation of sucrose 1 6323 9 kJ 2 2226 kJ 3 2226 kJ 4 can t predict

4 Trideuteroacetaldehyde solute is 90g non volatile non dissociative added to 17496g water to form a dilute ideal solution The vapour pressure of water has decreased from 300mm of Hg to 291mm of Hg The molecular weight of solute is 1 90 2 60 3 30 4 15

Which graph is true for 4p orbital of H like atom RPF Radial probability function H 4 RPF A RPF B RPF C RPF mn D RPF Your Answer D orrect AnswOK

6pts Part D Density of Metal Unknown number 1 4 for your unknown metal Mass of solid Initial volume of water Final volume of water 2pts Volume of solid ml 2pts Density of solid g mL 2pts Identity of metal Choose 2 53 40 g 51 3 ml 57 4 ml

lon a I II b I III c I II III 35 A complex containing K Pt IV and Cl is 100 ionised giving i 3 Thus complex is a K PtCl c K PtCl b K PtCl d K PtCl 36 Which of the fall d II III a 43 T 19 a C

4 5 0 V 3 The reduction potential of hydrogen negative if 1 p H 1 atm and H 2 0 M 2 p H 1 atm and H 1 0 M 3 p H 2 atm and H 1 0 M 4 p H 2 atm and H 2 0 M Rac AIEEE 2010 half cell will be AIEEE 2011

Consider a two level system of particles that is each particle can either be in the ground or the exited state The energy separation is A 2 kB 500K At what temperature 7 will the population of the exited state be that of the ground state At what temperature will the population of the two states equal

18 OH OH CH 3 4 Benzene and toulene form an ideal solution 3 mole benzene and 2 mole toulene are added V P of pure benzene and toulene are 300 200 mm of Hg respectively The V P of the solution in mm of Hg is 1 500 2 250 3 260 4 440

The analysis of a rock shows that the relative number of Pb206 and U238 atoms is Pb U 0 25 If t1 2 of U238 is 4 5 x 10 years then the age of the rocks will be A B C D 2 303 0 693 2 303 0 693 2 303 0 693 2 303 0 693 5 4 5 10 log 2 4 5 10 log 1 4 5 10 log 4 4 5 10 log 4 5

Calculate the number of equivalents in 10 litre of 0 5 MBa OH solution Ba 137 1 0 1 2 10 3 100 4 I Fac mer isomerism is associated with which one of the following complexes M central met 1 M AA 2 MA B 3 M AA 4 MABCD H Se has higher boiling point than H S This is best explained by

2 101 Zn Cu aq Cu Zn aq Reaction quotient is Q Zn Cu Qis of the type with OA 1 10 cell V E will be 1 1591 V when 1 Cu Zn 0 01 2 Zn Cu 0 01 3 Zn Cu 0 1 4 Zn Cu 1 12 Cu e Cu E x Variation of Ecell with log A Ecell ol volt X volta banb Log Q

Potassium salt of benzoic acid CH COOK can be made by action of potassium permanganate om toluene as follows CH CH3 KMnO4 CH COOK MnO KOH H O If the yield of potassium benzoate can t realistically be expected to be more than 71 what is the minimum number of grams of toluene needed to acheive this yield while producing 11 5 g of C H COOK

Ex 15 25 mL of hydrogen and 18 mL of iodine when heated in a closed container produced 30 8 mL of HI at equilibrium Calculate the degree of dissociation of HI at the same temperature Solution In this problem volume of the species is proportional to their concentration Thus

1 1 I and II II 2 I and III 4 III and IV 57 The temperature of a sample of gas is raised from 127 C to 527 C The average kinetic energy of the gas 1 Does not change 2 is doubled 3 is halved 4 cannot be calculated In the radioactive decay of X which of the following could be considered as incorrect statement 58 III 3 II and IV IV

You will appreciate that the ionization enthalpy and atomic radius are closely related properties To understand these trends we have to consider two factors i the attraction of electrons towards the nucleus and ii the repulsion of electrons from each other The effective nuclear charge experienced by a valence electron in an atom will be less than AH kJ mol 550 500 450 400 350 0 60 Li 520 10 Na 496 K 419 Rb 403 20 30 40 Atomic number 2 Cs 374 50 60 3 6 b O of elements of the second period as a

A homodiatomic molecule X have bond order 1 then which of the following prediction s will be correct for The difference of total number of bonding and antibonding e is 2 Molecule can be odd electron molecule Total number of bonding electrons is more than antibonding electrons Last e of X molecule must be entered into bonding molecular orbital

1 Number of significant figures in 10 3406g is 2 2 4 6 15 HO 3 3 ACES 74 5g of a metallic chloride contains 35 5g of chlorine The exact atomic weight of the metal is x and its specific heat is 0 0406 Cal g C The value of x is 1 150 3 156 9 Nitrogen forms two c law can be proved b 1 Constant Comm 2 Multiple Prop 3 Reciprocal 4 Conservati 10 x mole ator atoms The 2 157 6 4 155 02 mole of a diatomic 1 0 05 10