Physical Chemistry Questions

If bond enthalpies of N N H H and N H bonds are x x2 and x3 respectively AH for NH3 will be Question Type Single Correct Type 1 2 3 A X1 3x2 6x3 1 2x1 3 2x2 3x3 3x3 1 2x13 2x2 6Y Y 3x0

The pyknometric density of sodium chloride crystal is 2 165 x 10 kg m 3 while its X ray density is 2 178 10 kgm The fraction of unoccupied sites in sodium chloride crystal is X 2 5 96 x 10 4 5 96 x 10 3 1 5 96 3 5 96 10 1

ALLEN BEGINNER S BOX 1 01169 mmag Pre Medical Chemistry 123 1 The resistance of 1 N solution of CH COOH is 250 92 when measured in a cell of cell constant 1 15 cm The equivalent conductance will be 2 92 9 cm

Consider the following curve P 40 mmHg x X 1 mp E mole fraction y 50 mmHg 19 X 1 The above graph can be for which of the following mixture OCHCl H O On hexane n heptane Aniline phenol Read Las

56 Under isothermal condition a gas at 300 K expands from 1 L to 4 L against a constant external pressure go of 2 atm The heat absorbed by the gas is Aut 3 40 1 2 200 J Avtw 4 600 J n 1 L atm 100J 1 100 J 3 300 J

The specific conductivity of N 10 KCl solution at 20 C is 0 012 2 cm and the resistance of the cel containing this solution at 20 C is 56 2 The cell constant is 1 4 616 cm 2 0 672 cm 3 2 173 cm 4 3 324 cm

If the value of an equilibrium constant for a particular reaction is 1 6 x 10 2 then at equilibrium the system will contain 2015 a Mostly reactants b Mostly products c Similar amounts of reactants and products d All reactants

A compound of A and B crystallises in a cubic lattice in which the A atoms occupy the lattice points at the corners of the cube The B atom occupy the centre of each face of the cube The probable empirical formula of the compound is a A B c AB b AB d AB

Calculate the lattice energy of LiF s given that A AH for Lithium is 155 2 kJ mol sub B C D E A of Fluorine 333 kJ mol E AH for LiF s 594 1 kJ mol a 1011 6 kJ mol c 906 6 kJ mol AHis of 1 2 mole of F g is 75 3 kJ diss I E of Lithium 520 kJ mol b 2056 6 kJ mol d 573 6 kJ mol

In a reaction 2X Y the concentration of X decreases from 3 0 moles litre to 2 0 moles litre in 5 minutes The rate of reaction is b 5 mol L min a 0 1 mol L min c 1 mol L min d 0 5 mol L min

Moment of force can be defined as the product of force and distance from the line of action of force to the moment Centre Answer A O maximum B O any C

The equilibrium constants of the following are N 3H 2NH K K N 0 2NO H 0 H O K The equilibrium constant K of the reaction 2NH 0 2NO 3H O will be a KK K c K K K b K K K d K K K 2017

An open container of volume V contains air at temperature 300 K The container is heated to such a temperature so that amount of gas coming out is 2 3 of the amount of gas initially present in the container Find the temperature to which the container should be heated a 300 K c 900 K b 600 K d 1200 K

0 Cortisone is a molecular substance containing 21 atoms of carbon per molecule The mass percentage of carbon in cortisone is 69 98 What is the molar mass of cortisone A 176 5 B 252 2 D 360 1 C 287 6

Voltage of the cell Pt s H 1atm HOCN 10 M Ag 0 8M Ag s is 0 98V Calculate the Ka for HOCN Neglect H because of oxidation of H g Ag e Ag s E 0 8 V Given 2 303RT F 0 06

At a certain temperature the solubility of the salt AB is S moles per liter The general expression for solubility product will be 1 K x y S 2 K xy 3 K x y S 4 K x y Say

The density of a pure substance is its mass per unit volume The density of ethylene glycol has been measured to be 1097 Calculate the mass of 455 mL of ethylene glycol Be sure your answer has a unit symbol and the correct number of significant digits Solution O O O O O P m m V m m V 455 1 097 b0 m 414 77 g 415 g g L Write down the definition of density Solve for mass Put in the data given Use the calculator Round to the correct number of significant digits

A compound is formed by cation C and anion A The anions form hexagonal close packed hcp lattice and the cations occupy 75 of octahedral voids The formula of the compound is 2019 a C A b C A c C A d C A

10 4 6 10 23 a v 42 SO Cl 9 SO g Cl g K 2 9 10 atm atm SO Cl f 1 a 1 1 87 3 17 2 13 4 29 1 XX XV A cita 1 3 50 37 CO LAX

8 Schottky defect in crystals IS 1 Density of the crystal is increased 2 Unequal number of cations and anions are missing from the lattice 3 An ion leaves its normal site and occupies an interstitial site 4 Equal number of cations and anions are missing from the lattice

In s p overlapping wrong statement is 1 Nodal plane formed in ABMO 2 Some orbital may have higher energy than combining orbitals 3 Combining orbitals should have same symmetry 4 Nodal plane is found in BMO

When 100 mL of 1 0 M HCI was mixed with 100 mL of 1 0 M NaOH in an insulated beaker at constant pressure a temperature increase of 5 7 C was measured for the beaker and its contents Expt 1 Because the enthalpy of neutralization of a strong acid with a strong base is a constant 57 0 kJ mol this experiment could be used to measure the calorimeter constant In a second experiment Expt 2 100 mL of 2 0 M acetic acid Ka 2 0 x 105 was mixed with 100 mL of 1 0 M NaOH under identica conditions to Expt 1 where a temperature rise of 5 6 C was measured Consider heat capacity of all solutions as 4 2 J g K and density of all solutions as 1 0 g mL 1 2015 3 Enthalpy of dissociation in kJ mol of acetic acid obtained from the Expt 2 is A 1 0 B 10 0 C 24 5 D 51 4 The pH of the solution after Expt 2 is A 2 8 C 5 0 B 4 7 D 7 0 your A Dr Sup 20 whiny om bo state

c Both a b d None of these 74 A sample of pure compound contains 1 15 g of sodium 3 01 1022 atoms of carbon and 0 1 mol of oxygen atom Its empirical formula is a Na CO3 b NaCO c Na CO d Na CO 2

How many electrons are present in the kernel of P Z 15 1 2 3 Correct Answer 1 POLON 3 2532 10

Standard EMF of a galvanic cell involving 2e transfer is found to be 0 591 V at 25 C Calculate equilibri constant for the cell reaction 1 2010 2 1020 3 10 200 4 20010

A first line of Lymen series C last line of Paschen series B first line of Balmer series D last line of Bracket series Ratio of velocity of electron in 5th excited state and 3rd energy level for Het atom is A 9

Sulfur trioxide is not directly dissolved in water to form sulfuric acid because Sulfur trioxide is insoluble in water due to its covalent nature The reaction with water is so exothermic and evaporates the SO3 as dense fog which is difficult to condense SO3 does not react with water to form the acid SO3 could be converted to H SO3 when dissolved in pure water

A sample of 10 gm activated charcoal was brought into contact with CO gas contained in a vessel of 1 2 litre capacity at 27 C The pressure of CO was found to fall from 760 torr to 570 torr What volume of CO gas in mL is adsorbed per gm of charcoal at 570 torr and 27 C Assuming negligible volume of charcoal Correct answer 40 00

For a given reaction AH 35 5 KJ mol and AS 83 6 JK mol The reaction is spontaneous at Assume that AH and AS do not vary with temperature 2017 a T 298 K c T 425 K b T 425 K d All temperatures

Which one is the wrong statement a The uncertainty principle is AEX At h 4T b Half filled and fully filled orbitals have greater stability due to greater exchange energy greater symmetry and more balanced arrangement c The energy of 2s orbital is less than the energy of 2p orbital in case of hydrogen like atoms d de Broglie s wavelength h is given by my m mass of the particle v group velocity of the particle where

Which of the following is the strongest base 1 CH NH pK 9 42 3 CH N CH pK 8 94 2 CH NHCH pK 9 15 4 CH NHCH pK 8 89 ession

Consider the ions given below along with their size P 200 pm Q 300 pm R 350 pm w 100 pm x 150 pm y 200 pm Identify the incorrect statement O The solid wR undergo Frenkel defect O The solid yP undergo Frenkel defect O The solid xP undergo Schottky defect O The solid xQ undergo Schottky defect

If a is the length of the side of a cube the distance between the body centered atom and one corner atom in the cube will be AIPMT 2014 1 3 3 a a 2 4 a a

2HI g H g L g The equilibrium constant of the above reaction is 6 4 300 K If 0 25 mole each of H and I are added to th system the equilibrium constant will be a 0 8 b 3 2 c 1 6 d 6 4

1 A current liberates 0 504 g of hydrogen in 2 hours the amount of copper liberated from a solution of CuSO by the same current flowing for the same time would be 1 31 8 g 3 15 9 g CI 2 63 6 g 4 6 36 g 77 Na Corr 2 3

The solubility product of BaCl2 is 4 10 what will be solubility in mol litre Question Type Single Correct Type 1 2 3 4 4 x 10 3 3 2 10 9 1 x 10 3 1 10

The K of Ag CrO AgCl AgBr and Agl are respectively 1 1 x 102 1 8 x 10 5 0 x 10 9 8 3 x 10 Which one of the following salts will precipitate last if AgNO solution is added to the solution containing equal moles of NaCl NaBr Nal and Na CrO 2015 a AgCl c Ag CrO b AgBr d Agl

Value of dissociation constant of acetic acid is 10 where as dissociation constant of formic acid is 10 Which of the following will be the value of pK acetic acid pK formic acid 1 10 2 1 3 10 4 1

5 The intermetallic compound LiAg crystallizes cubic lattice in which both lithium and silver hav coordination number of eight The crystal class i 1 Face centred cube 2 Simple cube 3 Body centred cube LAX None of these

Reaction of Br with Na CO in aqueous solution gives sodium bromide and sodium bromate with evolution of CO gas The number of sodium bromide molecules involved in the balanced chemical equation is

The enthalpy of formation of CH g H O l and CO g are 74 8 kJ mol 285 5 kJ mol and 393 5 kJ mol respectively Then the standard enthalpy of combustion of CH g is a 890 3 kJ mol c 604 5 kJ mol b 604 5 kJ mol d 890 3 kJ mol

In a unit cell containing X2 Y3 and Z where X occupies 1 8th of tetrahedral voids Y3 occupies 1 2 of octahedral voids and Z2 forms ccp structure Then formula of compound is 1 X Y Z 3 XY Z 2 XY 74 4 XYZ

molecular mass of B is M then molecular mass of A is a M b 4 M C M d 2 M

Which will make basic buffer 2019 a 50 mL of 0 1 M NaOH 25 mL of 0 1 M CH COOH b 100 mL of 0 1 M CH COOH 100 mL of 0 1 M NaOH c 100 mL of 0 1 M HCl 200 mL of 0 1 MNH OH d 100 mL of 0 1 M HCl 100 mL of 0 1 M NaOH

Consider the following diagram P P Solution SPM Solvent Container 1 Container 2 SPM is the semi permeable membrane P and P2 are the pressure applied Identify the incorrect statement O If P P2 then liquid will flow from container 2 to container 1 O To stop the osmosis P must be equal to osmotic pressure To carry out osmosis P must be lesser than P2 If P2 is greater than P then reverse osmosis will occur

Sir for me balancing equation by ion electron method is more simpler as compared to the other method so can I gi ve more importance to this is it important to study the ot her Is there any questions that we can only get the answer b y doing this oxidation number method

Ans 2 70 Compound PdC1 6H O is a hydrated complex 1 molal aqueous solution of it has freezing point 269 28 K Assuming 100 ionization of complex calculate the molecular formula of the complex K for water 1 86 K kg mol 1 Pd H O CI 2 Pd H O C1 C1 2H O 3 Pd H O C1 C1 3H O 4 Pd H O CI 1 4H O 4 C CH Br Br Ar 74 1 2

Which of the following is incorrect statement about the Bragg s equation n 2d sine 1 n represents order of reflection 2 represents wavelength of UV rays used 3 0 represents angle of incidence 4 d represents distance between two parallel planes

A plot of volume V versus temperature T for a gas at constant pressure is a straight line passing through the origin The plots at different values of pressure are shown in figure Which of the following order of pressure is correct for this gas Volume mL P a P P P P c P P P P P P P Temperature K b P P P P

Which reaction with the following value of AH AS at 400 K is spontaneous and endothermic a AH 48 kJ AS 135 J K b AH 48 kJ AS 135 J K c AH 48 kJ AS 135 J K d AH 48 kJ AS 135 J K