Physical Chemistry Questions

6 How many moles of lead II chloride will be formed from a reaction between 6 5 g of Pbo and 3 2 g HC1I a 0 011 b 0 029 c 0 044 d 0 333 2008

the pressure at which PCI will be 20 dissociated temperature remaining same PCI dissociates according to the reaction PC1 PC13 g Cl g At 523 K K 1 78 atm Find the density of the equilibrium mixture at a total pressure of 1 atm P The gr N

Zinc is reacted with Hydrochloric acid to form zinc chloride and hydrogen gas The reaction is carried out in a glass container that has a mass of 14 7 grams After placing the zinc in the glass container the mass is 29 5 grams The hydrochloric acid is poured into the container and the zinc chloride is formed The excess hydrochloric acid is removed leaving the glass container and the zinc chloride which together have a mass of 37 5 grams What is the percentyield Zn 2HCl aq ZnCl H g

ne The following statements relate to adsorption of gases on a solid surface Identify the incorrect statement among them 2 1 Enthalpy of adsorption is negative Entropy of adsorption is negative On adsorption the residual forces on the surface are increased 3 4 On adsorption decrease in surface energy appears as heat

An aqueous solution is 1 00 molal in change will cause the vapour pressure of the solution to increase A B C D Addition of NaCl Addition of Na2SO4 Addition of 1 00 molal KI Addition of water

2 moles of an ideal monoatomic gas undergoes reversible expansion from 4 L 400 K to 8 L such that TV2 constant The change in enthalpy of the gas is b 3000R d 3000R a 1500R c 1500R

Ac227 has a half life of 22 year w r t radioactive decay The decay follows two parallel paths one leading the Th 27 and the other leading to Fr223 the percentage yields of these two daughters nucleides are 2 and 98 respectively What is the rate constant in yr for each of the separate paths

6 02 x 1020 molecules of urea are present in 100 mL solution The concentration of urea solution is AIEEE 2004 a 0 1 M c 0 02 M b 0 01 M d 0 001 M

4 Mno 1 mole in neutral aqueous disproportionates to 1 2 3 2 3 1 3 1 3 2 mole of MnO and mole of MnO and mole of Mn O and 4 mole of Mn O and 13 32 3 2 3 1 mole of MnO2 of Ma mole of MnO mole of MnO 2 mole of MnO

4 difficult to compute without 7 NH COONH s 2NH g CO g If equilibrium pressure is 3 atm for the above reaction K will be 3 4 27 4 1 27

36 Which of the following arrangements of electrons is most likely to be stable 3d 3d 4s 1 A 4s 2 41

1 The correct set of four quantum numbers for the valence electrons of rubidium atom Z 37 is a 5 0 0 1 2 1 c 5 1 1 2 JEE Mains 2014 1 b 5 1 0 d 5 0 1 2 1 2

In the following change 3Fe 4H O Fe O4 4H If the atomic weight of iron is 56 then its equivalent weight will be dib 1 42 2 21 3 63 4 84

29 A buffer of pH 9 26 is made by dissolving x moles of ammonium sulphate and 0 1 mole of ammonia into 100 mL solution If pK of ammonia is 4 74 calculate value of x

9 Gold number gives a the amount of gold present in the colloid rano b the amount of gold required to break the colloid CREMO c the amount of gold required to protect the colloid d none of the above FIORE

The heat of atomization of methane and ethane are 360 kJ mol and 620 kJ mol respectively The longest wavelength of light capable of breaking the C C bond is Avogadro number 6 02 x 1023 h 6 62 10 34 J s 1 49 103 nm 1 2 3 4 2 48 103 nm 2 48 104 nm 1 49 x 104

In disintegration reaction represented below B C 2 2 A t 2 1 t 2 2 It is found that the radioactive element B is in equilibrium with A If N and N are the number c radioactive elements A and B respectively then N where and 2 are average life of A and B respectively N N N A B C N N T T2 2 2 2 1 2 2 t 2 1 where 2 2 and transient equilibrium is achieved t 2 1 N 2 in the value of n D

Q16 Increasing order of thermal stability of I K CO A I II III II MgCO B II III I III Na CO C II I III D I III IL

7 If we add dilute aqueous solution of KI dropwise to AgNO aqueous solution the Agl colloid formed will have a negatively charged b positively charged Jam c neutral d nothing can be predicted loz siht AgI KN 90

The rate constant for the formation of NOBr at 127 C is 2 x 104 times that of the NOBr at 27 C The activation energy of the reaction is approx

sample of 0 15 g of the compound Pt NH3 Bry 2 zBr ignited and heated to decomposition oduced 0 0502 g of Pt A second 0 15 g sample was dissolved in water and titrated rapidly with 01 M AgNO3 solution 51 50 mL was required to precipitate all the ionic bromide A third 0 15 g ample was heated for two hours on a steam bath in a solution to which 0 2 mole of AgNO3 has een added This precipitated all the bromide no just the free ionic Br as AgBr The weight of ne precipitate thus produced was 0 20 g Find x y and z Pt 195 Ag 108 Br 80 N 14 and H 1

e solvent zing point ile solute qual to m s of 8 A Which of the following statements is correct The freezing point of water is depressed by the addition of glucose The degree of dissociation of a weak electrolyte decreases as its concentration decreases B C D Energy is released when a substance dissolves in water provided that the hydration energy of the substance is more than its lattice energy If two liquids that form an ideal solutio are mixed the change in entropy

2 What is the nature of the bond between B and O in C H5 2OBF3 a Covalent c Ionic bond b Coordinate covalent d Banana shaped bond

26 For the reaction PCI g PCI g Cl g the forward reaction at constant temperature is favoured by A introducing an inert gas at constant volume B introducing chlorine gas at constant volume C introducing an inert gas at constant pressure D increasing the volume of the container

When 1 0 mL of dil HCl acid is added to 100 mL of a buffer solution of pH 4 0 The pH of the solution 1 Becomes 7 r 2 3 Becomes 2 Does not change 4 Becomes 10

of electrons in the orbitals belonging to the same subshell does not take place until bers and Hund s rule of maximum multiplicity pairing vo electrons in an atom can have the each orbital belonging to that subshell has got one electron each i e is singly occupied This forms the basis of the electronic structure of atoms i ii EXERCISES i ii iii Calculate the number of electrons which will together weigh one gram Calculate the mass and charge of one mole of electrons Calculate the total number of electrons present in one mole of methane Find a the total number and b the total mass of neutrons in 7 mg of C Assume that mass of a neutron 1 675 x 10 27 kg Find a the total number and b the total mass of protons in 34 mg of NH at STP Will the answer change if the temperature and pressure are changed How many neutrons and protons are there in the following nuclei C 180 Mg Fe Sr 24 88 38 13 26 mber 7 and

Al2O3 is reduced by electrolysis at low potentials and high currents If 4 5x 104 A of current is passed through molten Al2O3 for 6 h what mass of aluminium is produced Assume 100 current efficiency at mass of Al 27 g mol a 9 0 10 g c 2 4 105 g b 8 1 104 g d 1 3 104 g

12 3 Bi2 t 130 sec decays T1207 81 by 83 83 a emission In an experiment starting with 5 moles of Bi211 how much pressure would be developed in a 350 L closed vessel at 25 C after 760 sec Antilog 1 759 57 41 1 0 68 atm 2 0 22 atm 3 0 34 atm 4 0 54 atm to

The following reaction is performed at 298 K 2NO g O g 2NO g The standard free energy of formation of NO g is 86 6 kJ mol at 298 K What is the standard f of formation of NO g at 298 K K 1 6 x 10 2 JEE Ma 1 86600 In 1 6 10 R 298 2 0 5 2 x 86 600 R 298 In 1 6 x 1012 3 R 298 In 1 6 x 1012 86600 10101

0 In S be the specific charge e m of cathode ray S be that of positive rays then which is true a S S b S S c S S d Either of these

9 For complete neutralisation of 25 mL of Na CO3 solution specific gravity 1 25 g mL 1 32 9 mL of HCl solution containing 109 5g of the acid per litre is required Calculate the volume of 0 84 N H SO4 that will be neutralised by 125 g of Na CO3 solution

33 Calculate the emf of the cell Pt H 1 0 atm CH COOH 0 1 M NH aq 0 01 M H 1 0 atm Pt Given that K CH COOH 1 8 x 10 K NH 1 8 x 10 A 0 92 V a C 0 35 V B 0 46 V D 0 20 V

41 It converts alcohols directly into gasoline by dehydration It is 42 a zeolite S c ZSM 5 An ultro filton ai b zeolite A stodola 16 d d chabazite ib 19tew 3 vodne to anng h

Subjective 65 The number of water molecule s directly bonded to the metal centre in CuSO4 5H O is 66 Based on VSEPR theory the number of 90 degree F Br F angles in BrF is 5

500 ml of 10 5 M NaOH is mixed with 500 ml of 2 5 x 10 5 M of Ba OH To the resultin solution 99 L water is added Calculate pH

Calculate the potential of an indicator electrode versus the standard hydrogen electrode which originally contained 0 1M MnO and 0 5M H and which was treated with 50 of the Fe2 necessary to reduce all the MnOto Mn 2 MnO4 8H 5e Mn 4H O E 1 51V 2 303RT F Given 0 06

56 A sea water sample has a density of 1 03g cm and 2 8 NaCl by mass A saturated solution of NaCl in water is 5 45 M NaCl How much water would have to be evaporated from 106 litre of sea water before NaCl would precipitate

PC13 g Cl2 g PC15 heat cont 5 g The equilibrium will shift in forward direction 1 By increasing conc of PCI 5 g 2 By decreasing pressure 3 By decreasing conc of PCL and Cl 3 g 2 g 4 By increasing pressure and decreasing temp

6 JEE 200 Statement 1 Pb 4 compounds are stronger oxidizing agents than Sn compounds Statement 2 The higher oxidation states for the group 14 elements are more stable for the heavier mem of the group due to inert pair effect A Statement 1 is True Statement 2 is True Statement 2 is a correct explanation for Statement 1 B Statement 1 is True Statement 2 is True Statement 2 is NOT a correct explanation for Statement 1 C Statement 1 is True Statement 2 is False D Statement 1 is False Statement is Trun

31 M is not stable and undergoes disproportionation to form M and M Calculate E for M dispropor tionation EM M 0 153 V EM M 0 53 V 1 0 683 V 3 0 754 V 2 0 367 V 4 0 3415 V

9 In the following first order competing reaction A Reagent Product B Reagent Prod The ratio of K K if only 50 of B will ha been reacted When 94 of A has been reacte is 1 4 06 3 2 06 2 0 246 4 0 06

1 1 182 2 0 182 3 0 818 26 For the reaction A g B g C g D g AHO and ASO are respectively 29 8 kJ mol 1 and 0 100 kJ K 1 mol 1 at 298K The equilibrium constant for the reaction at 298K is JEE Main Online 20161 1 1 0 x 10 10 3 1 0 x 1010 2 10 4 1 nposition to form a mixture of gases

0 5 mol NaCl is dissolved in 500g H O Th determine freezing point and boilling point solution Given K H O 1 8 K kg mol Kb H 0 0 5 K kg mol 1 1 8 C 100 5 C 2 3 6 C 101 C 3 3 6 C 99 4 0 C 100 C

The eq wt of Na S O as reductant in the reaction 2 2 3 Na S O3 H O Cl Na SO4 2HCl S is 2 Mol wt 2 4 Mol wt 8 1 Mol wt 1 3 Mol wt 6 mA

mol The molar conductivity of a 0 5 m solution of AgNO3 with electrolytic conductivity of 5 76 x 10 3 S cm 1 at 298 K is X 1 0 086 S cm mol 3 2 88 S cm2 mol 2 28 8 S cm mol 4 11 52 S cm mol

1 At 300 K and 1 atm 15 mL of a gaseous hydrocarbon requires 375 mL air containing 20 Q by volume for complete combustion After combustion the gases occupy 330 mL Assuming that the water formed is in liquid form and the volumes were measured at the same temperature and pressure the formula of the hydrocarbon is 1 C3H6 2 C3Hg 3 C Hg

muoride UF 6 from of uranium The molar mass of UF is 352 g mol Nitric acid is manufactured by the Ostwald process in which nitrogen dioxide reacts with water 3 NO g H O 1 2 HNO3 aq NO g How many grams of nitrogen dioxide are required in this reaction to produce 25 2 g HNO

30 On addition of NaOH to CH COOH solution 60 of the acid is neutralised If pK of CH3COOH is 4 7 then the pH of the resulting solution is 1 More than 4 7 but less than 5 0 2 Less than 4 7 but more than 4 0 3 More than 5 0 4 Remains unchanged

No of un A metal has BCC structure and the edge length d its unit cell is 3 04 The volume of the unit cell i cm will be a 0 1 1 6 x 10 21 cm 3 6 02 x 10 23 cm 2 2 81 x 10 23 cm 4 6 6 x 10 24 cm

Metal M of radius 50 nm is crystallized in type and made cubical crystal such that face of unit cells aligned with face of cubical crystal If the total number of metal atoms of M at all faces of cubical crystal is 6x1030 then the area of one face of cubical crystal is Ax10 6 m Find the value of A