Physical Chemistry Questions

1st attempt Jul See Periodic Table O How much 5 60 MNaOH must be added to 600 0 ml of a buffer that is 0 0190 Macetic acid and 0 0270 M sodium acetate to pH to 5 75

27 Cyclohexane and Ethanol at a particular temperature have vapour pressures of 280 mm and 168 mm respectively If these two solutions having the mole fraction of cyclohexane as 0 32 are mixed the total vapour pressure is found to be 376 mm at the same temperature Should the mixture warm up or cool down after mixing Justify

H S is bubbled into a 0 4 M NaCN solution which is also 0 04 M in each Ag CN and Cd CN 4 2 Ksp Ag2S 10 50 Ksp CdS 7 1 10 28 K Ag CN 10 20 and K Cd CN 412 7 8 x 1018 Which of the following is incorrect CdS will precipitate first Concentration of S2 when Ag2S will precipitate is 1 6 10 9 M Concentration of S2 when CdS will precipitate is 5 76 10 1 M Ag S will precipitate first

while VO For the decomposition of H O aq it was found that Vo t 15 min was 100 mL at 0 C and 1 atm maximum was 200 mL at 0 C and 2 atm If the same reaction had been followed by the titration method and if V CM t 0 had been 40 mL what would V CM t 15 min have been A 30 mL KMnO4 KMnO4 B 25 mL C 20 mL D 15 mL

4 100 mm Hg 38 K for H g water system is 5 34x107 torr If the partial pressure of H over a solution at 25 C is 760 torr then determine the solubility of hydrogen Assume density of H O and solutions are same 1 6 4 x 10 3 mol L 1 2 7 89 10 4 mol L 1 3 5 9 x 10 3 mol L 1 4 8 9 x 10 4 mol 1 1

23 NaCl is doped with Ti4 in such a way that Ti ions replace Nat at the edge centres of NaCl lattice The no of voids created per mole of NaCl are a 4 5 1023 b 1 35 x 1024 c 1 8 1024 d 3 38 x 1023

Question Number 68 Question Id 9046847157 Question Type MCQ Option Shuffling Yes Is Question Mandatory No Correct Marks 1 Wrong Marks 0 The decomposition of NO is an endothermic process A sample of NO2 contained in a vessel at constant volume is heated at a temperature of t C to attain equilibrium 2NO2 g 2NO g O2 g The equilibrium pressure changed by 35 What will be the mole fraction of NO at equilibrium Options 90468423852 0 20 90468423853 0 26 90468423854 0 52 90468 22955

Partial Marks 3 If all the four options are correct but ONLY three option Partial Marks 2 If three or more options are correct but ONLY two optie Partial Marks 1 If two or more options are correct but ONLY one option Zero Marks 0 If none of the options is chosen e the question is unans Negative Marks 2 in all other cases For Example If first third and fourth are the ONLY three correct option options without selecting any incorrect option second option in this cas Selecting any incorrect option s second option in this case with or with In a rock salt structure of AB select the correct options s A is forming foc while B is going to all octahedral void location Bis forming foo while A is going to all octahedral void location O 2a 4r must be correct must be correct

ction is C 1 42 An element A in a compound ABD has oxidation number A It is oxidised by Cr O2 in acidic medium In the were used for number experiment 1 68 x 10 3 mole of K Cr O7 3 26 10 3 mole of ABD The new oxidation A after oxidation is a 3 c n 3 b 3 n d n

4 The Boltzmann distribution a is a measure of energy state accessibility b describes the distribution of energy associated with the dominant configura c quantifies the average energy of a chemical system that is far from equilibri d determines what specific energy level the atom molecule populates

4 The equivalent conductivity of monobasic acid at infinite dilution is 348 ohm cm eq If the resistivity 1 of the solution containing 15 g acid molar mass 49 in 1 litre 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

In the reaction COCI g CO g Cl g at 550 C when the initial pressure of CO Cl are 250 and 280 mm of Hg respectively The equilibrium pressure is found to be 380 mm of Hg Calculate the degree of dissociation of COCI at 1 atm What will be the extent of dissociation when N at a pressure of 0 4 atm is present and the total pressure is 1 atm A 0 32 and no change C 0 4 and 0 3 B 0 32 and 0 4 D In presence of N dissociation cannot take place

07 3 moles of KMnO4 reacts completely with 9 10 moles of X in acidic medium to give XO3 and Mn2 Value of n will be O 10 3 O 2 3 05 3 Marks 4 1 5 62 66 70 74

21 Relative lowering in vapour pressure containing 1 mole K SO4 in 54g H O is K SO4 is 100 ionised 1 55 3 4 2 55 4 1 1 2

A gas expands from 3 dm to 5 dm against a constant pressure of 3 atm The work done during expansion is used to heat 10 mole of water at temperature 290 K Calculate final temperature of water Specific heat of water 4 184 J g K Given 1 atm 101 33 J 1 290 81 K 2 290 61 K 3 290 41 K 4 290 21 K

In a hypothetical reaction 2B aq C aq A aq 1st order decomposition A is optically active dextro rototory while B and C are optically inactive but B takes part in a titration reaction fast reaction with H O Hence the progress of reaction can be monitored by measuring rotation of plane of polarised light or by measuring volume of H O consumed in titration In an experiment the optical rotation was found to be 0 30 at t 20 min and 0 15 at t 50 min from start of the reaction If the progress would have been monitored by titration method volume of H O consumed at t 30 min from start is 30 ml then volume of H O consumed at t 90 min will be A 60 ml B 45 ml Le 5 52 5 ml D 90 ml

SO gas is entering the environment at a constant rate of 6 93 10 g L day due to emission of polluting gases from thermal power plant at Kota but at the same time it is decomposing and following first order kinetics with half life of 100 days Based on these details select the correct statement s from the following a Concentration of SO in Kota is 1 25 x 10 M assume SO present in air reaches steady state b If 10 L of air is passed through 1 L pure water assuming all SO is dissolved in it and the resulting solution is titrated against 1 N NaOH solution 15 ml of NaOH solution is required to reach the end point c An industry is manufacturing H SO4 at the rate of 980 kg per day with the use of SO in air and it should use 8 10 L air per day d If SO emission is stopped then after 1000 days its concentration will reduce to 1 22 x 108 M

1 The equivalent weight of P in the following reaction is 4 P NaOH H O PH NaH PO 4 M 3 M 6 where M molar mass a C b d M 11 M 2 8 9

Which of the following is wrong a Cathode rays have constant e m ratio b e m ratio of anode rays is not constant c e m ratio of protons is not constant d e m ratio of particles is constant

8 When beryllium carbide is reacted with water gas X of characteristic smell is given out The oxidation state of heaviest constituent element of gas X should be a 1 b 1

Solve the following 1 A sample of argon has a volume of 4 Liters when the pressure is 1 atm What volume doe aragon occupy at 1 5 atm 2 200mL of hydrogen gas is kept at constant temperature it has a pressure of 1 5atm Calculate the pressure when compressed to

Some amount of commercial AgNO3 of 50 purity is dissolved in 50 ml of water It is treated with 50 ml of KI solution The silver iodide thus precipitated is filtered off Excess of KI in the filterate is M treated with 50 ml of KIO3 solution in presence of conc HC1 when all the iodine is converted into 10 M KIO3 under similar conditions What ICI 25 ml of the same stock solution of KI requires 30 ml of 10 is the amount of AgNO3 initially taken a 0 68 g b 0 54 g c 0 45 g d 2 g

d Between 6 and 7 15 Which of the following options will be correct for the stage of half completion of the reaction AB a AG 0 b AG 0 C AG 0 d AG RT In K 19

18 A 0 50 M solution of KI reacts with excess of H SO in KIO solutions according to the equation 6H 51 10 31 3H O Which of the following statements is true a 200 mL of the KI solution reacts with 0 10 mole KIO b 100 mL of the KI solution reacts with 0 060 M of H SO c 0 5 litre of the KI solutions produces 0 15 mole of 1 d None of the above

Which statement is false b c a Elements of VB group are transition elements Elements of VA group are all metalloids Elements of IA and IIA groups are metals Elements of IVA group are neither strongly electronegative nor strongly electropositive d

Suppose you have taken a dilute solution of oleic acid in such a way that its concentration becomes 0 01 cm of oleic acid per cm of the solution Then you make a thin film of this solution monomolecular thickness of area 4 cm by considering 100 spherical drops of radius 3 40m Where x is 10 3 cm Then the thickness of oleic acid layer will be xx10 14 m

DH for the reaction IF5 g IF 3 g F2 g is KJ Given the data below IF g F g IF 3 g IF g 2 F g IF5 g Select one a 35 Ob 35 O c 1135 Od 1135 Oe 355 DH 390 kJ DH 745 kJ

Which one of the following solutions will have the greatest concentration of hydroxide ion Select one O a 0 368 M calcium hydroxide O b 1 10 M rubidium hydroxide O c 0 368 M potassium hydroxide O d 0 368 M Sulfuric acid O e 0 368 M ammonium hydroxide

27 IfZ is the number of atoms in the unit cell that represents the closest packing sequence ABC ABC number of tetrahedral voids in the unit cell is equal to the b 2Z a Z c Z 2 d Z 4 I

A balloon weighing 50 kg is filled with 1 00 000 moles of Helium gas at 1 atm pressure and 25 C What will be its pay load if it displaces equal mo ambient air Atomic weight of He 4 Avearge atomic weight of ambient air 30 Pay load Weight of air displaced Total weight of balloon A 2550 kg B 3000 kg c 450 kg

10 In an ionic compound A X the radii of A and X ions are 1 pm and 2 pm respectively The volume of unit cell of crystal AX will be a 27 pm c 125 pm b 64 pm d 216 pm

5 A solution is prepared by adding 2 g of a substance A to 18 g of water Calculate the ma per cent of the solute Ans 10 6 56 g of Nitrogen reacts with 22 g of hydrogen to form ammonia Find 1 The limiting reagent of the reaction 2 The amount of reactant in excess 3 The amount of ammonia formed 7 Convert the following numbers in scientific notation 1 0 30054 2 5604 3 0 00000045

A 2 0 g sample of a mixture containing sodium carbonate sodium bicarbonate and sodium sulphate is gently heated till the evolution of CO ceases The volume of CO2 at 750 mm Hg pressure and at 298 K is measured to be 123 9 mL A 1 5 g of the same sample requires 150 mL of M 10 HCI for complete neutralization Calculate the percentage composition of Na SO4 in the original mixture

1 SiO CH MgBr CO 1 Ethyl acetate 2 KO Dry ether Y 3 BaO H O Z identify Z from the following 2 Acetic acid 3 Propanoic acid 4 Cs0 4 Methyl acetate pantanal on rogation with aluminium fortiory butoxide in the racon of goatona given

Review the pK data of the following equilibria and point out which buffer is to be used to study the hydrolysis of methyl acetate at pH 9 25 cy 1 HSO SO2 H pK 1 92 2 H PO HPO2 H pK 7 21 3 CO aq H O HCO3 H pK 6 37 4 HCO3 CO3 H pK 10 25 X 21

20 The value of equilibrium constant of a reaction changes with change of temperature and the change is given AH AH P dT RT2 where enthalpy change AH is taken as constant in the small temperature range by van t Hoff equation dln K dT If for reaction A 3B 2C a plot of In K eq versus for 1 T a reaction is shown then which of the following condition will be favourable for formation of product C C Keq 1 T a Low temperature and high pressure b High temperature and high pressure High temperature and low pressure

d All of these 6 In one of the following reactions HNO does not behave as an oxidising agent identify it a I 10 HNO 2 HIO 10NO 4H O b 3Cu 8 HNO 3Cu NO3 2NO 4H O c 4Zn 10HNO 4Zn NO NH NO 3H O d 2HNO P O 2HPO N O 7 The equivalent weight of Mu

D 3 d 5 C 1 37 Equivalent weight of Mn in the following reaction is Mn 55 Mn Mn MnO 3 a 27 5 c 110 b 55 d 165

3 Water is oxidized to oxygen during photosynethesis 4 Water can act both as an acid and as a base The buffer system which helps to maintain the pH of blood between 7 26 to 7 42 is 1 H CO HCO 2 NH OH NH C 3 CH COOH CH COO 4 CH CC

The equivalent conductances of two strong electrolytes at infinite dilution in H O where ions move freely through a solution at 25 C are given below ACH COONa 91 0 S cm equivalent What additional information quantity one needs to calculate of an aqueous solution of acetic acid What additional information quantity one needs to calculate of an aqueous solution of acetic acid 1 A of chloroacetic acid CICH COOH 2 A of NaCl 3 A of CH COOK 4 The limiting equivalent conductance of H 2

For a given reaction DS 69 0 J mol K and the reaction is spontaneous at temperature above the crossover temperature 439K The value of DI kl mol assuming that DH and DS do not vary with temperature DS Delta Entropy DH Delta Enthalpy Select one O a 6 36 x 10 3 O b 30 3 O c 1 57 x 10 4 O d 1 57 x 10 4 Oe 30 3

16 k for the reaction 2 BaO 2 BaO O g is s s 1 6 10 atm at 400 C Heat of reaction is 25 14 kcal What will be the number of moles of O gas produced at 500 C temperature The reaction is carried in 2 litre vessel a 0 022 x 10 10 c 10 24 b 10 8 d 0 046 10 5

Arrange the following in order of decreasing number of unpaired electrons 1 Fe H 0 11 Fe CN III Fe CN 1 IV I II III 2 I II III IV 3 III II I IV The compound SiH N is expected to be IV Fe H O 4 II III I IV

83 1 XYZ 2 X YZ 3 X YaZs 4 XsY4Z8 Identify the option which represents the correct products of the following reaction OF PHCHO CH CHO Aldols PH CH CH CHO I III OH DLH OH CH CH CH CHO 2 L III II PhCH COPh IV OH O 11 CH CH C Ph 3 II III 4 L III IV

81 AAJ KA TOPPER An unknown compound A dissociates at 500 C to give products as follows 4 g B g C g D g Vapour density of the equilibrium mixture is 50 when it dissociates to the extent to 10 What will be the molecular weight of compound A 1 120 2 130 3 134 4 140 MY CCOON

Pb Cu Zn and Ni ions are present in a given acidic solution On passing hydrogen sulphic gas through this solution the available precipitate will contain 1 PbS and Nis 2 PbS and CuS 3 CuS and ZnS 4 CuS and Nis

A sample of air containing 20 O2 and 80 N is dissolved in water when total pressure of air is 1 atm The solubility of N and O in terms of mole fraction is x and y This sample is taken at a height of H above sea level where pressure of air is 0 4 atm and temperature is 300 K and solubility of N and 0 in terms of mole fraction is x and y Assume that value of Henry s constant remains x y same at sea level and H The value of is

RH ion exchange resin can replace Ca2 ions in hard water as RH Ca2 RCA 2H If 1 L of hard water after passing through RH has pH 3 then hardness in parts per million of Ca2 is A B 10 ppm Your Answer 40 ppm

Consider the oxidation of nitric oxide to form NO 2NO g O g 2NO g a Express the rate of the reaction in terms of changes in the concentration of NO O and NO b At a particular instant when 0 is decreasing at 0 2 mol L s at what rate is NO2 increasing at that instant

3 Sandmeyer s reaction 4 Claisen condensation A greenish yellow gas reacts with an alkali metal hydroxide to form a halite which can be used in fireworks and safety matches The gas and halides respectively are 1 Br KBRO 2 Cl KCIO 3 1 Nalo 4 Cl NaCIO Sodium extract of an organic substance gives a blood red color with FeCl It contains the elements