Physical Chemistry Questions

View In Three elements A B and C having oxidation number 1 3 and 2 respectively which of the following is correct molecular formula 2 3 4 rect Answer 3 A2BC AB 2C3 AB 2C4 A2B3C4

Aqueous solution of nickel sulphate on treating with pyridine and then adding a solution of sodium nitrate gives dark blue crystals of a Ni py 4 SO4 c Ni py 4 NO 2 b Ni py 2 NO 2 d Ni py 3 NO 2SO4

A strong acid B strong base C weak acid K 1 8 x 10 5 D a weak base K 2 10 and x O represents volume of that compound for the same concentration and area of overlapping represents extent of mixing The buffer is A B B

Identify the basic salt solution KCI aq ZnCl aq NaNO3 aq LiC H3O2 aq CaBr aq According to Lewis theory H is an acid because it accepts electron pairs H is a base because it donates electron pairs H is an acid because it donates electron pairs H is a base because it accepts electron pairs

1 2 3 3 4 4 2 47 The given plots represent the variation of the concentration of a reactant R with time for two different reaction i and ii The respective order of the reactions are ii 1 1 0 In R 2 1 1 time R 3 0 1 time 4 0 2

Total vapour pressure of mixture of 1 mole of A 150 torr and 2 mol B P B 240 torr is 220 mm Hg In this case PA Question Type Single Correct Type 1 There is positive deviation from Raoult s law 2 There is negative deviation from Raoult s law 3 There is no deviation from Raoult s law

PCI PCI and Cl eqimolar mixture is at equilibrium at 6 atm pressure If an inert gas is introduced into the mixture with a mole fraction of 0 25 and the pressure is maintained at 6 atm only what is the degree of dissociation of PCI at new equilibrium 0 87 YOUR ANSWER CORRECT ANSWER IS

55 An unsaturated hydrocarbon X absorbs two hydrogen molecules on catalytic hydrogenation and also gives following reaction Az NH 0 2 10 A X 56 B 3 oxo hexanedicarboxylic acid X will be 1 2 3 The weight of cilvor at yet 10 dienlaged by a quantity of electricity which dienlange 560 ml of a at

10 2 marks The boiling point of a pure solvent is 353 23 K When 90 grams this solvent is used to dissolve 1 80 g of a non volatile solute its boiling pa is raised by 0 87 K Find the molar mass of the solute Boiling point elevati constant Kb for the solvent is 2 53 K kg mol

3 Define the shift of the equilibrium for the following reaction CO2 g C s 2CO g AH 172 kJ in case of a Increase of temperature Explain your answer b Decrease of pressure Explain your answer Write the expression for the equilibrium constant of the reaction

30 It is more convenient to obtain the molecular weight of an unknown solute by measuring the freezing point depression than by measuring the boiling point elevation because 1 Freezing point depression is a colligative property whereas boiling point elevation is not 2 Freezing point depressions are larger than boiling point elevations for the same solution 3 Freezing point depressions are smaller than boiling point elevations for the same solution 4 Freezing point depression depends more on the amount of the solute than boiling point elevation TE 2 and 2 ba the throchold wavelength and wavelength of incident light the velocity of photoelectron 21

Max score 2 Neg score 0 5 An atom s emission spectrum can be observed in ground state An emission spectrum from an atom will contain all wavelengths of energy Electrons in the 2s orbitals of Boron and Carbon have same amount of energy Gamma rays are higher in energy than Infrared waves

58 Which one of the following graphs between molar conductivity A versus is correct 1 2 Am E KCI NaC1 3 KCI C NaCl KCI 19 NaCl

The phosphorus in a 0 2300 g sample was precipitated as the slightly soluble NH4 3PO4 12 Mo O3 This precipitate was filtered washed and then redissolved in acid Treatment of the resulting solution with an excess of Pb resulted in the formation of 0 2922 g of PbMo 04 Express the results of this analysis in terms of percent P2O5

1 For the reaction 2N O 4NO 0 The values of rate constant and rate of reaction are respectively 3x10 s and 2 4x10 mol L s concentration of N O in mol L will be 2 0 8 1 0 4 Hanife 3 1 2 4 0 6

The pK value for HCN is 9 40 Would a buffer prepared from HCN and KCN with a pH of 8 90 be considered to be an effective buffer A buffer in which the mole ratio of KCN to HCN is 1 8 has a pH of 9 65 Would this buffer solution have a greater capacity for added acid H O or added base OH

Q 7 For a Fajan s titration it was determined that a 15 mL solution of potassium chloride was 0 04 M in concentration The end point of the titration was observed at the burette reading of 16 3 mL What is the concentration of the standard silver solution used in this titration Max score 2 Neg score 0 5 0 1 M 0 04 M 0 037 M 0 0025 M

A bar magnet is held at a right angle to a uniform magnetic field The couple acting on the magnet is to be halved by rotating it from this position The angle of rotation is 1 60 2 45 3 30 4 75 A battery of internal resistance 40 is connected to the network of resistance as shown in the figure To

The vapour pressure P of three aqueous solutions X Y and Z of same solute but with different concentrations are plotted against temperature T in Kelvin X Y Z a The concentration of these solutions are in the order A X Y Z C Z Y X B X Y Z D X 7 Y

Consider the following reaction C s O g CO g x KJ CO g O g CO g y KJ 2 Heat of formation of CO g Question Type Single Correct Type 1 2 3 KJ x y mol KJ x y mol KJ y x mol

105 An electrochemical cell is set up as Pr s H H CH COOH 0 IM latm 0 1M H PI s 1 atm The emf of cell will not be zero because A the temperature is constant B emf depends on molarities of acids used C acids used in both half cells are different D pH values of both acid solution are not same

1 2 3 56 The weight of silver at wt 108 displaced by a quantity of electricity which displaces 560 mL of O at STP will be volume of 1 mole of gas at STP is 22 4L 57 1 54 9 g 2 5 4 g 3 10 8 g 4 108 0 g The increasing order of basicity for the following intermediates is from weak to strong

X 5 1 mark Freundlich adsorption isotherm is given by k pn If the graph of m X m against P has a slope k what is the value of n

Q 4 Enthalpy of reaction for N g 3H2 g 2NH3 g is 92 KJ What will be the effect of increasing the temperature on the extent of reaction Max score 2 Neg score 0 5 equilibrium will shift towards the reactants equilibrium will shift towards the product No change will occur as all reactants and products are gaseous equilibrium will move equally towards roactants and products

21 Which of the following metal ion forms unstable Cu in this und complex with CN 1 Ag 1 CU CCN 2 Zn II 3 Cu II 4 Cr 1 22 Which of the following ion does not exist 1 Cul 2 VO 3 WO 2 4 CrO 2

Consider the following groups 1 OAC II OMe IV O SO2 CF3 III O SO Me The order of leaving group nature is Question Type Single Correct Type 1 V 2 IV III 3 IV

97 50 mL of 20 8 w V BaCl2 aq and 100 mL of 9 8 w V H SO4 aq solutions are mixed Molarity of Cl ions in the resulting solution is At mass of Ba 137 a 0 333 M b 0 666 M c 0 1 M 98 100 mL of 10 NaOH w is added to 100 ml of 10 IC an d 1 33 M m1

Q 6 Select the reaction which can not be employed for precipitation titration Max score 2 Neg score 0 5 2 AgNO3 CaCl2 Ca NO3 2 10 CO2 g 8 H O K SO4 BaCl2 BaSO4 s 2 KCI 2MnO4 5 H C2O4 6 H 2 AgCl s 2 Mn AgNO NaSCN AgSCN s NaNO

Q 10 Presence of a catalyst in a reaction will affect the equilibrium in the following manner Max score 2 Neg score 0 5 equilibrium will move towards the reactants equilibrium will move towards the products helps to reach the equilibrium faster Effect on equilibrium can not be determined

1 The Henry s law constant for the solubility of N 2 gas in water at 298 K is 1 0 x105 atm The mole fraction of N 2 in air is 0 8 The number of moles of N2 from air dissolved in 10 moles of water at 298 K and 5 atm pressure is a 4 0x10 4 c 5 0 10 4 b 4 0 10 5 d 4 0x10 6 idered to be completely

Problem 11 How many carbon atoms are present in 0 35 mole of C6H12O6 Problem 12 How many nitrogen atoms are in 0 25 mole of Ca NO3 Problem 13 How many molecules of water are present in the one mL of water Problem 14 How many molecules are present in one mL of water vapours of STF Problem 15 What is the weight of 3 01 x 1023 molecules of ammonia

3 1 4 dihydroxy anthraquinone 4 1 hydroxyl anthraquinone 84 Given that E values of Ag Ag K K Mg Mg and Cr Cr are 0 80V 2 93V 2 37V and 0 74V respectively Therefore the order for the reducing power of the metal is 1 Ag Cr Mg K 2 Ag Cr Mg K 3 Ag Cr K Mg 85 Phosphate fertilizers when added to water leads to 4 Cr Ag Mg K

Q18 Rajat took 100 g of 50 w w sugar solution He divided the solution into 4 equal parts He added 5 g of sugar in 1st part A and 20 g of water in 2nd part 8 then he mixed these two parts and labelled the solution as C The concentration w w of solution C is A 60 B 40 30 D 55 Answer B 4

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

The following data were obtained in a bomb calorimeter experiment Weight of coal burnt 0 996g Weight of water in calorimeter 2490g Weight of bomb calorimeter etc 3900g Rise in temperature of water 2 592 C Find the higher calorific value of the fuel If the fuel sample contains 6 hydrogen calculate its lower calorific value latent heat of steam 587 cal g

A sample of 100 ml of 0 10 M acid HA 1 10 5 is titrated with standard Ka 0 10 M KOH How many ml of KOH is required to be added when the pH in the titration flask will be 5 00 A 0 B C 10 100 D 50

8 A gas is heated in such a way that its pressure and volume both becomes double Then by decreasing temperature some of the molecules of air has been added in container to maintain the doubled volume and pressure Assuming of initial number of moles has been added in for the purpose The fraction by which the temperature must have been raised finally of initial absolute temperature 1 4 times 2 16 5 times 3 4 54times 4 1 5times

The overall formation constant of Co NH3 in aqueous solution is 10 at 298 K and the standard potential for reduction of Co aq and Co NH aq as follows Co aq eCo aq E 1 90V Co NH3 aq e Co NH aq E 0 IV If the overall formation constant of the Co NH3 ion is 10 at 298 K Then the 2 303RT value of x would be Given 0 06 F A 35 0 B 31 2 C 39 6 D 29 3

13 a 2g of benzoic acid dissolved in 25 g of benzene shows a depression in freezing point equals to 1 62K Molal depression constant of benzene is 4 9K Kgpermol What is percentage dissociation of molecule if it forms dimer b Explain reverse osmosis

Problem 13 How many molecules of water are present in the one mL of water Problem 14 How many molecules are present in one mL of water vapours of ST Problem 15 What is the weight of 3 01 x 1023 molecules of ammonia Problem 16 If it requires one second to count four wheat grains calculate the ti

c 40 mL 30 mL 30 mL d 55 mL 20 mL 25 mL 102 A bottle of an aqueous H O2 solution is labelled as 28 V H O2 and the density of the solution in g mL is 1 25 Choose the correct option a Molality of H O2 solution is 2 b Molarity of H O2 solution is 5 d None of these c Molality of H O2 solution is 2 15 103 The impure 6 g of NaCl is dissolved in water and then treated with excess of silver nitrate solution The mass of precipitate of silver chloride is found to be 14 g The purity of NaCl

a 1 79 b 2 143 c 1 951 d None of these 91 0 2 mole of HCl and 0 2 mole of barium chloride were dissolved in water to produce a 500 mL solution The molarity of the Cl ions is a 0 06 M b 0 09 M c 1 2 M d 0 80 M 92 Calculate the mass of anhydrous HCl in 10 mL of concentrated HCl density 12 g ml

20 ml of 0 1 M weak acid HA has Ka 10 5 is mixed with Solution of 10 ml of 0 3 M HCl and 10 ml of 0 1 M NaOH Find the value of A HA A in the resulting Solution A 2 104 B 2x10 5 C 2x10 D 0 05

HX is a non volatile weak acid with a K of 10 9 It reacts with NaOH to form a salt Nax The osmotic pressure in atm of a 0 001 M Solution of NaX at 298 K is Equal to the osmotic pressure A of 0 001 M NaCl at the same temperature B C D Greater than the osmotic pressure of 0 001 M NaOH at the same temperature Twice the osmotic pressure of 0 001 M NaOH Less than the osmotic pressure of 0 001 M NaCl

a 0 06 M b 0 09 M c 1 2 M d 0 80 M 92 Calculate the mass of anhydrous HCl in 10 mL of concentrated HCl density 1 2 g mL solution having 37 HCl by mass a 4 44 g b 4 44 mg c 4 44 x 10 3 mg 93 Calculate the molality of 1 I solution of 80 H SO GAN d 0 444 g

i 100 ml of 0 1 M HCI mixed with 50 ml of water ii 50 ml of 0 1 M H SO4 mixed with 50 ml of water iii 50 ml of 0 1 M H SO4 mixed with 100 ml of water iv 50 ml of 0 1 M HCI mixed with 50 ml of water A i and ii B i and iii C ii and iii

0 Two electrolytic cells containing AgNO3 abd CuSO4 solution connected in series A steady current of 2 5A was passed till 1 078g of Ag is deposited How long did the current flow What mass of copper will be deposited atomic mass of Ag 107 8 Cu 63 5

When CO g is passed over red hot coke it partially gets reduced to CO g Upon passing 0 5 litre of CO g over red hot coke the total volume of the gases increased to 700 mL The composition of the gaseous mixture at STP is AIEEE ONLINE 2012 1 CO2 3 CO2 200 mL CO 500 mL 0 0 mL CO 700 mL 2 CO 350 mL CO 350 mL 4 CO 300 mL CO 400 mL

Which of the following statement s is are correct 1 The pH of 1 0 10 8M solution of HCI is 8 2 The conjugate base of H PO is HPO 3 Autoprotolysis constant of water increases with temperature 4 When a solution of a weak monoprotic acid is titrated against a strong base at half neutralization point pH pk

Problem 7 Problem 8 Problem 9 What is the weight of one atom of H in g at wt of H 1 008 How many g atoms and no of atoms are there in 120 g carbon Calculate the mass in g of a 2 mole of CO b 2 N molecules of CO