Physical Chemistry Questions

mergy released O g 2e 2e 0 AHeg 744 7 KJ mole The positive value of AHeg is due to g A Energy is released to add on 1 e to 0 B Energy is required to add on 1 eto 0 is much more than energy released when le is added toO g C Energy is needed to add on le to O D None of the above is correct

If you are reacting 4 00 g benzophenone MM 182 22 g mol and you want to add 1 5 equivalents of NaBH4 MM 37 83 g mol what is the minimum volume in mL of 2 0 M HCl you need to add to ensure the reaction is fully quenched

b Non stoichiometric cuprous oxide Cu O can be prepared in the laboratory In the oxide copper to oxygen ratio is slightly less than 2 1 Can you account for the fact that it is a p type semiconductor 2

3 Enthalpy of sublimation of iodine is 24 cal g at 200 C If specific heat of I s and 1 I vap are 0 055 and 0 031 cal g K respectively then enthalpy of sublimation of iodine at 250 C in cal gis JEE Main 2019 12 April Shift 1 a 2 85 c 22 8 b 5 7 d 11 4

56 When photons of energy 4 25eV strike the surface of a metal A the ejected photoelectrons have maximum kinetic energy TA expressed in eV and de Broglie wavelength 24 The maximum kinetic energy of photoelectrons liberated from another metal B by photons of energy 4 70V is Tg TA 1 50 eV If the de Broglie wavelength of these photoelectrons is AB 224 then which is not correct a The work function of A is 2 25 eV b The work function of B is 3 70 eV c TA 2 00eV d TB 0 5eV

Calculate the volume of H g at 273 K and 2 00 atm that will be formed when 475 mL of 0 725 M HC1 olution reacts with excess Mg to give hydrogen gas and aqueous magnesium chloride 0 56 L II V 7 1 12 L 1 93 L 2 24 L 3 86 L 22 49

For the reversible PC13 Cl2 system PC15 the relationship between degree of dissociation a of PCI5 and the equilibrium constant Kp of the above equilibrium is 1 2 3 4 Kp P Kp Kp 1 P Kp 1 P Kp 1 V 1 P Kp

A mol L 2 5 10 4 5 0 10 4 1 0 10 3 B Initial rate mol L 1 at mol L 300 K 320 K 3 0 10 5 5 0 x 10 4 2 0 x 10 3 6 0 10 5 4 0 10 3 6 0 10 5 1 6 10 a Calculate the order of the reaction with respect to and with respect to B b Calculate the rate constant at 300K c Calculate the pre expontential factor

97 For which of the following the radius will be same as for hydrogen atom having n 1 a He n 2 ran Be n 2 b Li2 n 2 d Li n 3 her of electrons with the azimuthal quantum

6 The correct order of acidic strength is 1 HCIO4 HCIO3 HCIO2 HCIO 2 HCIO3 HBrO3 HIO3 3 H3PO2 H3PO3 H3PO4 4 All of these

0 0 g of gaseous ammonia and 6 50 g of oxygen gas are introduced into a previously evacuated 11 0 L vessel If the ammonia and oxygen then react to yield NO gas and water vapor what is the final ga pressure inside the vessel at 23 C I 1 84 atm IV 1 23 atm II 4 42 atm V 3 67 atm III 2 21 atm 22 49

4 0 50 A 69 Consider the following conversions i O g e O g AH ii F g e F g AH iii Cl g e Cl g AH3 iv O g e O g AH4 Then according to given information the incorrect statements is 1 AH is more negative than AH and AH 2 AH is less negative than AH 3 AH AH and AH are negative whereas AH is positive 4 AH and AH are negative whereas AH and AH are positive

D 786 999 1012 1256 Which of the following sequence is correct for decreasing order of ionic radius A Se 2 I Br O 2 F C Se 2 I Br F 0 2 B I Se 2 O 2 Br F D Se 2 Br 0 2 F Which 11

AH for CaCO3 s CaO s CO2 g is 176 kJ mol 1 at 1240 K The AU for the change is equal to A 160 kJ B 165 6 kJ C 186 3 kJ D 180 0 kJ For a chemical reaction 2A g 5B g at 27 C the difference Then the ratio X R A Zero C 5 100 2A B g 5 between AH and A E is X B Unity D 1 5 x 103

In an experiment one mole of Na2CO3 10H2O was heated to a temperature by which it got converted into Na2CO3 xH O The H O vapours obtained in this process were used to convert CuSO4 into CuSO4 5H O If 0 6 moles of CuSO4 was hydrated value of x is

The ionic radii of Ni Pd Pt2 are given below Radius in ions Ni2 0 72 1 44 1 48 Pd pt2 60 Ionic radius is increases from Ni2 to Pd but Pd to Pt ionic radius is almost constant This is due to 1 Poor sheilding of 4f electrons towards 7s 2 Imperfect sheilding of 4f electrons towards 6s electron 3 Poor screening of 5f electrons towards 7s 4 All of these

If burning 15 g of C H6 in excess of air gives x kJ heat energy then enthalpy of combustion of ethane is 15 x kJ mol 1 30 x kJ mol 1 2 x kJ mol 1

If Ksp of a weak salt AB is 10 14 M then the solubility of sa in mol L is 1 10 1 10 7 10 10 hr min 10 14

pka PK a2 2 and c pKa 113 In which of the following cases is the solution of AgCl unsaturated sp a Ag Cl Ksp b Ag Cl Ksp c Ag Cl Ksp d Ag Cl Kp d pK and pK a2 a 114 When equal volumes of the following solutions are mixed the precipitation of AgCl 10

In a non stoichiometric sample of ferrous oxide with NaCl structure the ratio of Fe to Fe wa found to be 0 15 The fraction of octahedral sites occupied by vacancies is A 0 0843 B 0 0923 C 0 0613 D 0 0232

Triad I N O Na Triad II N C 0 1 O Choose the species of lowest IP from triad I and highest IP from triad II respectively N 0 B Na C C N N D O C The correct values of ionization energies inkl mot of Ra Na Ha INE

3 K 4 Rb 88 Consider the following transformation X n X 9 X X2 9 9 Then correct relation between n and n is 1 n n 2 n 2xn 3 2xn n

K Which ionisation potential IP in the following equations involves the greatest ammount of energy A K K e P Lit Ca e Li 2 e C Fe Fet e D Cat The t LOS QU

5 The electronic configuration of some neutral atoms are given below 1 1s 2s 2 1s 2s 2p 3 1s 2s 2p4 In which of these electronic configuration would you expect to have highest i IE A 3 1 ii IE 2 1 C 3 2 Which of the following pairs has glomer D c f 4 1s 2s 2p 3s D 2 4

8 Zz In a ccp structure of X atoms Y atoms occupy half of octahedral holes If one Y atom and X atom from each unit cell is replaced by Z then the formula of compound will be 1 X4Y Z 2 X3YZ 3 X3Y Z 4 X3Y3Z In a face centerd lattice of Y and Y Y atoms are present at the corners while Y atoms are at face centers

Which one of the following will have a low heat of fusion 1 a covalent solid 2 an ionic solid Diamond belongs to the crystal system 2 triclinic cubic 3 tetragonal In a simple cubic cell an atom at the corner contributes to the unit cell 3 a metallic solid 4 a molecular s 4 hexagonal

A sample of gas expanded isothermally from 1 L to 10 L against constant external pressure of 1 atm The work done during the process is 1 L atm 9 L atm 10 L atm

Which of electron affinity 1 3 Decrease Increase 2 Increase 4 decrease 0 0 CI CH O 0 Decrease Cle Increase decrease Decrease Increase decrease Increase S F S Decrease F Increase S Increase S Increase ws correct change in 8

aqueous solution of sodium hydroxide contains 2 00 g NaOH in 50 0 mL of solution the number of moles of NaOH present equals the molar concentration of the solution is how many moles of NaCl would be formed if 50 0 mL of 1 0 mol L HCI solution were added to the 50 0 mL of NaOH solution

Solubility of Ni OH 2 will be maximum in 0 1 M aq solution of NiS 0 1 M aq solution of NaOH 0 1 M aq solution of Ca OH 2 0 1 M aq solution of H SO4

61 180 Standard molar enthalpy of formation at 298 K is zero for Br 1 Smonoclinic H O 1 Mark for Review 03 g

26 Calculate the solubility product of Co Fe CN in water at 25 C Given conductivity of saturated solutions of Co Fe CN 6 is 2 06 10 6 21 cm and that of water used is 4 1 10 72 cm The ionic molar conductivities of Co and Fe CN are 86 0 52 cm mol and 444 0 2 cm mol respectively 1 7 87 x 10 7 3 7 87 10 8 2 7 87 x 10 6 4 7 87 10 9

200 0 g of metal specific heat 0 440 at 150 C was placed in 1 00 L of water at 25 0 C What is the final temperature of the nickel water mixture density of water 1g mL specific heat of water 4 184 J g C I 51 3 C II 26 3 C III 27 6 C IV 35 8 C V 62 5 C 22 49

102 The pH of a solution containing 0 4 M HCO3 and 0 2 M CO is K H CO3 4 x 10 7 K HCO3 4 10 a 10 4 b 10 1 c 6 1 d 10 7 103 The pH of the resultant solution of 20 mL of 0 1 MH3PO4 and 20 mL of 0 1 M Na3PO

9 15 The transition in He ion in balmer series that would have the same wave number as the first Lyman line in the hydrogen spectrum is Final Results 0 2 1 0 5 3

The initial concentration of the reactant in a zero order reaction is 1 386 mol L 1 The half life of the reaction is 20s Calculate the rate constant 2 the concentration of the reactant after 30s from the initiation of the reaction

The approximate quantum number of a circular orbi diameter 20 6 nm of the hydrogen atom according Bohr s theory is Mxm a 10 c 12 www 14 d 16

A square array of 196 tubes 1 25 cm in diameter is used to condense steam at 1 atm pressure Water flowing inside the tubes maintains the outside surface temperature at 92 C Calculate the condensation rate for tube lengths of 2 0 m

HBPB OH The times required to consume a small but constant amount of HBPB at varying initial HBPB and OH concentrations were measured and are recorded below Determination 1 1 The following data were collected at 20 C for the reaction of bromphenol blue HBPB2 and hydroxide ions OH is shown below 2 3 3 BPB H O HBPB M 7 22 x 106 7 22 x 10 3 63 x 10 OH M 1 00 0 25 1 00 Rate 2 Rate 1 k A B k A B Time s 75 290 152

1 86A 2 3 22A 3 If the unit cell of a mineral has cubic close packed ccp array of oxygen atoms with m fraction of octahedral holes occupied by aluminium ions and n fraction of tetrahedral holes occupied by magnesium ions m and n respectively are JEE Adv 2015 D 1 1 2 8 2 1 4 3 1 112 22 4 8 JEE Main 2016

4 CI occupy octahedral holes in the lattice The most unsymmetrical system is 1 Cubic 2 Hexagonal 3 Triclinic Schottky defect occurs mainly in electrovalent compounds where 1 positive ions and negative ions are of different size 4 Orthorho

What is the formation reaction for MgSO4 s I MgNO3 aq H SO4 aq 2 HNO3 aq MgSO4 s II Mg 2 aq SO42 aq MgSO4 s III Mg s S rh 2O2 g MgSO4 s IV MgO s SO3 g MgSO4 s V None on the answers 22 49

Ratio of equilibrium constants for the reaction CO 3 H CH4 H O Kc 10 and 1 1 CH 3 H O CO H is 1 101 3 104 3 103

100 ml of 0 1 M acetic acid is completely neutralized using a standard solution of NaOH The volume of ethane obtained at STP after the complete electrolysis of the resulting solution is A 112 ml C 224 ml B 56 ml decomposition by coment D 560 ml

MgU 1 12 0 ions ock salt structure No of nearest neighbour of Mgion are 2 8 0 2 ions 3 6 0 2 ions 4 4 0 ions d 6 If the distance between Na and C ions in NaCl crystal is a pm what is the length of the cell edge 1 2a pm 4 a 4 pm Which of the following expressions is correct in the case of a sodium chloride unit cell edge length a 2 a 2 pm 3 4a pm

Complete the sentences with the correct form of the verbs given in brackets I would have phoned you come cricket play the offer accept her she would have come invite 1 If he 2 If it hadn t rained we 3 If I were you I 4 If you 5 1 6 If I had lots of money I 7 If you had run you 8 Ifl 9 If we 0 I wouldn t do that if I Ifl If I knew her address I him if I had been free meet round the world travel the bus catch in America I would earn a lot of money live now we would get there by lunchtime start you be her she might have come phone

n be stant 4 0 1 M Ca NO3 2 and 0 1 M Na2SO4 121 What will be major product in following reaction CH CH 1 2 3 4 122 CH CH CH CH CH CH CI CI CH CH CI P hv

Metallic lustre is explained by 1 diffusion of metal ions 3 excitation of free protons In an antifluorite structure cations occupy 2 oscillation of loose electrons 4 existence of bcc lattice u F Nazo

Select correct dlagi dill about acidic strength of oxides P 06 1 Increase ALO P4 06 2 Decrease P 06 3 Increase Increase Increase AL2 034 Al2O3 P 06 Increase Decrease Decrease Increase SO 3 Decrease Cl 07 Decrease Increase SO3 Decrease Ch 2 07 SO3 Increase CO7 SO 3 Increase

The correct values of ionization energies in kJ mol of Be Ne He and N respectively are A 899 2080 1403 2372 B 2080 899 1403 2372 899 2080 2372 1403 D 899 1403 2080 2372 WFL 1 fal c 125