Physical Chemistry Questions

78 3 g of a volatile metal chloride when vapourised occupies volume of 6 72 litre at STP When 10 44 g of the metal chloride was heated with an excess of Mg powder 7 6 g of MgCl was produced along with metal Consider the metal chloride is a monomer even in vapour phase and contain only 1 metal atom per formula Then identify the correct statement s A The atomic mass of metal is 119 u B The oxidation number of the metal is 3 C 4 76 g of metal is obtained on the reaction of above sample of metal chloride with Mg powder D The mass of Mg powder used in the above reaction of metal chloride with Mg is 2 4 g if the Mg powder used is 80 pure

The ratio of mass percent of C and H in an organic compound CxHyO is 6 1 If one molecule of the above compound CxHyOz contains half as much oxygen as required to burn one molecule of compound CxHy completely to CO2 and H O The empirical formula of compound CxHyOz is

Which of the following set of quantum numbers n l m s represents the unpaired electron of Cu ion Atomic number of Cu 29 1 On 3 1 2 m 2 s 2 1 O n 4 1 0 m 0 s 2 O n 4 1 0 m 0 s On 3 1 1 m 1 s 1 IN 2 1 2

16 Calculate enthalpy of formation of C diamond if enthalpy of atomisation of C graphite 710 kJ mot and energy required to break C C bond in diamond solid 354 05 kJ mot A 2 9 kJ mol B 1 9 kJ mol C 3 3 kJ mol D 0 9 kJ mol

Incorrect statement about graphite is It has layered structure Each layer is composed of planar pentagonal rings of carbon atoms Each carbon atom is sp hybridised It conducts electricity

Ne at 6 s The oxidation potential of electrode M M N aq 298 K is E When temperature in C is doubled and concentration is made half the electrode potential becomes E Which is correct 1 E E 2 E E 3 E E

16 Ferrous sulphate crystals decompose on heating to give Fe2O3 SO2 and gas X Gas X is Only one correct answer A 02 B SO3

7 The oxidation of malate to oxaloacetate can be coupled to the reduction of NAD to NADH Malate NAD oxaloacetate NADH H Mitochondrial concentrations of the reactants are as follows Oxaloacetate 5 0 x 10 mol L Malate 1 1 x 10 mol L NAD 7 5 x 10 mol L NADH 9 2 x 10 mol L What is the free energy change in the mitochondrion for the reaction

For the ionic compound A3B which of the following statements are correct if radii of A and B ion are respectively 5 x and 2 x and the lattice points have hcp arrangement th of tetrahedral voids are vacant rd of total voids are vacant in compound The coordination number of B is 8 The coordination number of A is 8

In the phenomenon of osmosis through the semipermeable membrane 1 Solvent molecules pass from solution to solvent 2 Solvent molecules pass from solvent to solution 3 Solute molecules pass from solution to solvent 4 Solute molecules pass from solvent to solution

The radius of the second Bohr orbit for hydrogen atom is in Planck s constant h 6 6262 10 34 Js mass of electron 9 1091 x 10 1 kg charge of electron e 1 60210 10 1 C permittivity of vacuum the radius of first Bohr orbit is 0 6 E 8 854185 x 10 12 kg 1 m 3 A

In a buffer solution containing equal concentration of B and HB the K for Bis Then pH of the buffer solution is us apo grave pars made de Budu HB 50 J B 10 av po gw pH Jod Options 1 8 2 7 3 6

When a man walks on rough horizontal surface then nature and direction of force of friction between shoes and ground A Dynamic forward B Dynamic backward C Static forward D Static backward

Ferric oxide crystallises in a hcp of oxide ions with two out of every three octahedral voids occupie by ferric ions Derive the formula of ferric oxide In a closed packed arrangement there is one octahedral site corresponding to each ato constituting the lattice Therefore number of oxide ions per unit cell in hcp arrangement is 6 Number of octahedral voids 6 1 6 2 6x 4 3 Number of Fe 3 ions 6 x Formula of the compound Fe O 2 or is Fe O3 4 6

166 20 of SO diffuses through a porous partition in 60 seconds Volume of O diffuse under similar conditions in 30 seconds will be B 14 14 l D 28 14 l A 12 14 l C 18 14 l

How much volume in ml of 0 2 M CH3COOH solution should be added in 500 ml of 0 1 M NaOH solution to make a buffer of pH of 5 0 pKa CH3COOH 4 7 1 500 ml 3 375 ml 2 200 ml 4 400 ml

10 ml of a mixture of CO CH4 and N2 exploded with an excess of oxygen gave a contraction of 6 5 ml There was a further contraction of 7 ml when the residual gas treated with KOH Find the volume of CO CH4 and N 2 respectively is

At 323K the vapour pressure in mm of Hg of a methanol ethanol solution is represented as P 120X 140 Where X is the mole fraction of methanol in liquid solution at equilibrium The value of P ELOH is 260 mm 20 mm 120 mm 140 mm

Fe5C2 produced from martensite during tempering at 1000C Assuming that martensite is formed during isothermal transformation of 15 kg wrought iron ferrite 70 purity kg E carbide 9 86 O 8 79 10 62 O 11 40 O 12 04

Marking scheme o 4 If the correct integer is typed in the provided space o O In all other cases An element undergoes a reaction as shown X 2e X2 31 35 eV atom If the energy released is used to dissociate 4 gms of H molecule equally into H H where H is excited state of H atoms where the e travels in an orbit whose circumference is equal to 4 times its de Broglie s wavelength Determine the least no of moles of X that would be required Bond energy of H 5 0 eV molecule

1 Consider an aqueous solution 0 1 M each in HOCN HCOOH COOH and H PO for HOCN H in H IOCN HOCN we can write K HOCN this expression refers to A H ions released by HOCN B Sum of H ions released by all monoprotic acids C Sum of H ions released only the first dissociation of all the acids D Overall H ion concentration in the solution

In electrolysis of acidic water 10 A current is passed for 200 seconds The total volume of the gases evolved at the electrodes at NTP is as a wer 104 Dahod 200 50g Few Day was NTP 3 Jesase sa Dasdealy Jawse augan suasoro dod Options 1 320 ml 2 230 ml 3 348 ml 120 ml

pH of 10 M HCI aqueous solution is nearly Options 2 4 7 10 Solution Answer 3

144 The rates of diffusion of SO3 CO PC13 and SO are in the following order A PCI 3 SO3 SO CO B CO SO PCI 3 SO3 C SO SO3 PCI3 CO D CO SO SO3 PC 3

pH of 0 2 M aqueous solution of sodium bel will be pKa of benzoic acid 4 2 1 9 50 28 75 3 10 25 4 7 50 2 Which among the following is smallest in size

The mass of NaCl added in 100 g water to ma its boiling point 100 C is k 0 51 K kg mol 1 10 68 g 2 5 34 g 3 2 67 g

Af solute and solvent interactions are more than solute solute and solvent solvent interactions then 1 It is ideal solution 2 It is non ideal solution with positive deviation 3 It is non ideal solution with negative deviation Con t predicted LA

The ratio of moles of water as water of crystallisation in CaCl and SrCl is 1 2 2 1 hr n 1 1

0 1 kg of milk at 10 C is added to 0 3 kg of coffee in a cup of mass 0 3 kg both at 90 C Calculate the final temperature of the mixture in C Assume that there are no heat exchanges with the surroundings Assume that the specific heat of milk equals the specific heat of coffee 4200 J kg 1 0C 1 The specific heat of the cup is 840 J kg 1 0C 1 O 73 43 O 83 O 63 O 53

above 138 Predict which of the following reaction s has a positive entropy change I Ag aq Cl aq AgCl s II NH CI s NH g HCI g N g 3H 9 III 2NH g A I and II C II and III B III D II

Which among the following cannot show disproportionation Options PH3 H O S 8 HCIO Solution

For the cell Pt s Br 1 Br 0 010 M H 0 030 M H g 1 bar Pt s if the concentration of Br becomes 2 times and the concentration of H becomes half of the initial value then emf of the cell 1 Doubles 3 Eight times 2 Four times 4 Remains same

Consider a beam of neutrons where every neutron in the beam has kinetic energy E 0 05eV Take the half life and the rest energy of a neutron to be T1 2 900 In2 sec and mc 810MeV respectively Find the fraction of the number of neutrons which will decay before the beam travels a distance of d 10m If your answer is x x 10 then fill value of x

SolveLancer Test What is the effect on boiling point of a particular substance on Venus and Mars w r t Earth SolveLancer Test a Increase Decrease b Increase Increase c Decrease Decrease d Decrease Increase a

Chemistry Sec 1 Maximum Marks 24 This section has 6 questions The answer to each question is a SINGLE DIGIT INTEGER ranging from 0 to 9 both inclusive Marking scheme o 4 If the correct integer is typed in the provided space o 0 In all other cases Light from a discharge tube containing hydrogen atoms falls on the sodium metal surface The kinetic energy of the fastest moving photoelectron emitted from sodium is 0 73eV If these photons are emitted in hydrogen atom due to the transition from energy 1 to n and the work function of sodium metal is 1 82eV then the minimum value of 1 1 is

26 Density of 3M solution of NaCl is 1 25 g mL Calculate the volume of water required to make 1000 mL of t NaCl solution Consider the density of water as 1 g mL A 1074 5 mL B 1250 mL C 824 5 mL D 1000 mL

1 If absorbance of the fertilizer solution corresponds to the concentration of 2 78 x 104 M PO4 what would be the concentration of P O5 O 0 01916 g L O 0 057498 g L O 0 07664 g L 09 0 3832 g l

Question 67 pH of 10 M aqueous solution of CH COOH is pK CH COOH 4 7 Options 1 4 2 85 3 7 4 7 Solution Answer 2

o vapour But for the change of state to occur the wat er must absorb 540cal g of heat to change i nto vapour which is called latent heat of va pourization of water Do you think during evaporation the liquid a bsorbs this much heat to turn to vapour If no then how does it change to vapour T his cannot be by specific heat of water caus e specific heat of water is the amount of he at required to increase the temperature of 1 g of water by 1 C It doesn t change the stat e Lauess

2013 11 The number of carbon atoms per unit cell of diamond unit cell is a 6 c 4 b 1 d 8 NEET 2013 12 A metal crystallises with a face centred cubic lattice The edge of the unit cell is 408 pm

3 Consider a first order decomposition process A A A plot of concentration of A and A v time is shown below At time t percentage of reactant decomposed is 2 Concentration A Ato no A3

c hydrogen bonding interactions d dipole dipole interactions 1997 8 For two ionic solids CaO and KI identify the wrong statement among the following a CaO has high melting point b Lattice energy of CaO is much larger than that of KI c KI has high melting point d VI

The reactant which is used to precipitate th IVth group basic radical and the type o precipitation will be 1 H S dil HCl Sulphide 2 NH OH NH4Cl Chloride 3 NH OH NH4Cl Hydroxide 4 H S NH4OH Sulphide

When potassium chlorate KCIO3 is strongly heated it gives KCI and 02 The percent loss in weight after heating a pure sample of KCIO3 is nearly At wt of K 39 CI 35 0 16 amu KCIO s KCI s 0 g O 40 O 60 O 50

Which of the following is the laboratory method of preparation of dihydrogen Electrolysis of warm aqueous barium hydroxide solution between nickel electrodes Reaction of steam on hydrocarbons at high temperatures in the presence of catalyst Donction of zing with aquQOUS alkali

5 The pure crystalline substance on being heated gradually first forms a turbid liquid at constant temperature and still at higher temperature turbidity completely disappears The behaviour is a characteristic of substance forming

i How structure of a co valent molecule can be determined from dipole moment data Explain with example The dipole moment of chlorobenzene is 1 55D The bond distance of C H CI is 2 8 Estimate the percentage of ionic character of the bond 2 2

If 2 4 g of a metal displace 1 12 litre hydrogen at norm temperature and pressure equivalent weight of metal would be 12 24 CORRECT ANSWER

35 The edge length of face centred unit cubic cells is 508 pm If the radius of the cation is 110 pm the radius of the anion is a 144 pm c 288 pm b 398 pm d 618 pm 1998 36 Schottky defect in crystals is observed when a density of the crystal is increased b unequal number of cations and anions are

150 The ratio of mass percent of C and H of an organic compound C H O is 6 1 If one molecule of the above compound C H O contains half as much oxygen as required to burn one molecule of compound C H completely to CO and H O The empirical formula of compound C H O is A C H O C C H O B C H O 3 D C H O 2