Physical Chemistry Questions

Physics The vapour pressure of a solution having solid as solute and liquid as solvent is Options Directly proportional to mole fraction of the solvent Question Palette inversely proportional to mole fraction of the solvent Directly proportional to mole fraction of the solute Inversely proportional to mole fraction of the

4 In a cubic close packed structure of mixed oxides the lattice is made up of oxide ions one eight of tetrahedral voids are occupied by divalent X2 ions while one half of the octahedral voids are occupied by trivalent ions Y ions then the formula of the oxide is 1 XY 04 3 X5Y 5010 2 X YO4 4 X5Y4010

A certain dye absorbs light of 1 4530 and then fluorescence light of 5080 Assuming that under given conditions 47 of the absorbed energy is re emitted out as fluorescence calculate the ratio of number of quanta emitted out to the number of quanta absorbed A photon of 300 nm is absorbed by a gas and then re emits two photons One re remitted photon has wave

22 The volume of nitrogen gas at 0 C and 1 013 bar required to cover a sample of silica gel with unimolecular layer is 129 cm gm of gel Then the surface area per gm of the gel will be if each nitrogen molecule occupies 16 2 10 m I 568 m gm 2 5 68 m gm 3 5680 m gm 4 5680 cm gm 4

1 Se Se 2 Te Te 4 0 0 Given the two concentration of HCN K 10 are 0 1 M and 0 001 M respectively What will be the ratio of degree of dissociation 1 I 2 0 1 3 0 003 4 0 01 64 1 Se Se 3 S S HCN K 10 0 1 M 0 001 M 1 I 3 0 003 2 Te Te 4 0 0 facut 13 factGA EI 2 0 1 4 0 01

Which of the following statement is true hr m O A catalyst alter Gibbs energy of a reaction O The action of the catalyst cannot be explained by intermediate complex theory O A catalyst does not change the equilibrium constant of a reaction O Catalyst catalyses the non spontaneous reaction

8 3 5 R in 2 4 R In 2 2 The enthalpy of atomisation of PH is 954 kJ 78 mol and that of P H is 1485 kJ mol What is the bond enthalpy of the P P bond 1 213 kJ mol 2 200 kJ mol 3 253 kJ mol 4 313 kJ mol 10 ml each of IM HCI and IM H SO are 79 3 5 R In 2 4 R In 2 PH P H 1485 kJ mol P P vtt 1 213 kJ mol 3 253 kJ mol IM HCI IM H SO 954 kJ molta 2 200 kJ mol 4 313 kJ mol 10 mi IM NaO

5 6 A sample of H gas is at 298 K and 1 00 bar Deuterium 2H appears in the sample at its natural abundance of 0 02 Calculate the collision frequency y in s with which any given D molecule in the sample collides with another D molecule

Which of the following is are correct regarding Valence Bond Theory regarding co ordination compounds It gives a quantitative interpretation of thermodynamic stability or kinetic stability of complexes It does not distinguish between strong and weak ligands It explains the colour exhibited by coordination compounds It makes exact predictions regarding tetrahedral and square planar geometry

Which of the following mixtures can NOT act as a buffer 0 HCl CH3COONa 2 1 molar ratio respectively CH3COOH NaOH 2 1 molar ratio respectively CH COOH NaOH 1 2 molar ratio respectively CH COOH NaOH 1 1 molar ratio respectively

The paramagnetic property of the oxygen molecule is due to the presence of unpaired electrons present in 1 02 and 2 2 02 and 3 2 and 2

Consider the formation of Cu NH3 4 2 from Cu If the stepwise stability constant are represented C NH KINH KI CANH NH NH K KINH B NH KINH B NH NH NH K Ka If the values of log of K K2 K3 and the overall stability constant B of the complex are log K 4 log K 3 2 log K3 1 8 log B 11 then the value of at equilibrium is Cu NH Cu NH 0 01 times the concentration of NH3 100 times the concentration of NH3 250 times the concentration of Cu2 104 times the concentration of NH3

Which of the following reactions is an example of heterogeneous catalysis NO2SO3 NO 2 2 2SO2 g O2 g 1 200 g O2 g 4 CH CHO 3 200 g O2 g Pt s 2CO 2CO CO CHA

A catalyst in the finely divided form is most effective because 1 less surface area is available 2 more active sites are formed 3 more energy gets stored in the catalyst 4 none of these

When benzoic acid heated in presence of NH3 a product X is formed Reaction a X Br KOH Reaction b Y CHCl3 KOH Y other products C Z other products If initially 1 mole of benzoic acid is taken then find the sum of total number of moles of products formed in balanced reactions a and b 19 00

w fdv Pext For a system undergoing a particular process the work done is a w jav V 2 RT V b V This equation is applicable to a A System that satisfies the van der Waals equation of state B Process that is reversible and isothermal C Process that is reversible and adiabatic D Process that is irreversible and at constant pressure

2A g BCJ approach of equilibrium concentrations of A B and I are 0 5 M 3M and 1 5M respectively At the start of the reaction I was absent but I was present cinitial concentration of PE 0 5 M Identify the correct statement 4 the concentration of D at equilibrium is 4 5 M 6 R 450 M 0 25 2 Al Kc S A B CD CD

A metal crystallises in FCC lattice If edge length the cell is 4 108 cm and density is 10 5 g cm th the atomic mass of metal is 1 101 2 2 50 6 3 202 3 4 None

In a reaction for every 10 C rise of temperature the rate is tripled If the temperature is increased from 10 C to 50 C the rate of the reaction will become O 81 times O 9 times O 243 times

Find out the number of photons emitted by a 60 watt bulb in one minute if wavelength of an emitted photon is 620 nm a Calculate the kinetic energy of a photoelectron emitted by a sodium surface when light of wavelength 400 nm is incident on it The work function of sodium is 2 28 eV

Plancks Quantum Theory Photoelectric Effect 1 Assume that 10 17 J of light energy is needed by the interior of the human eye to see an object How ma photons of green light 2 495 nm are needed to generate this minimum energy B 30 C 35 A 25 D 40

The atomic mass of a diatomic gaseous element is 19 Which of the following statement s is are correct regarding the element O The mass of one atom of the element is 19 amu The mass of NA molecules of the element is 38 g The volume of No atoms of the element is 22 4 L at 0 C and 1 atm The volume of 2 g molecules of the element is 44 8 L at 0 C and 1 atm

Chemistry Classify following solutions in to true solution colloid and suspensions Write names of solute and solvent present in any five from these solutions Milk Paint Blood Lemonade Salt solution Rain water Coke Air Tooth paste Shaving cream Gem stones Tea Cold coffee

8 The standard reduction potential values of three metals X Y and Z are 0 52 3 303 and 1 18V respectively The order of reducing power of the corresponding metal is 1 Y Z X 2 X Y Z 3 Z Y X 4 Z X Y

If rate constant for a first order reaction is 60 s the how much time will take to reduce the initial 1 concentration of the reactant to its 2 3 10 2 s S 4 6 x 10 s 6 9 10 2 S 16 th value

Given Enthalpy of ionization of two acids AH HCN 45 2 kJ mol AH CH COOH 2 1 kJ mol Which relationship for the two acids is true 1 pK HCN pK CH COOH 2 pK HCN pK CH COOH 3 pK HCN pK CH COOH 45 2 2 1 4 pK HCN B pK CH COOH 80 faci AH HCN 45 2 facile i AH CH COOH 2 1 kJ f 1 pK HCN pK CH COOH 2 pK HCN pK CH COOH 3 pK HCN pK CH COOH 45 2 4 pK HCN 2 1 pK CH COOH

2 The conductivity of four electrolytes P Q R S in ohm cm are as follows P 5 x 10 Q 1 x 10 0 R 7 x 108 S 9 2 x 10 The one which offers highest resistance to passage of electric current is 1 P 3 R 2 S 4 Q

7 Choose the reaction s from the following options for which the standard enthalpy of reaction is equal to standard enthalpy of formation JEE Adv 2019 Paper A S8 s O g SO g 8 C 2C g 3H g C H g B 2H g O g 2H O 1 D 0 9 03 9

26 Calculate AG for the galvanic cell 2Cr s 3Cd aq 2Cr 3 aq 3Cd s Er 3 Cr 0 74 V EC Cd 0 40 V Senco 1 196 86 kJ mol 3 65 62 kJ mol 2 98 43 kJ mol 4 164 05 kJ mol

Amount of ice that will separate out on cooling a solution containing 31 g ethylene glycol in 200 gm water to 9 3 C will be Kf water 1 86 K kg mol O 90 g O 100 g hr m O 110 g

Which of the following statements is correct O Order of a reaction cannot be zero O Molecularity is applicable to elementary as well as complex reaction O Order is applicable to elementary as well as complex reactions O For complex reaction order is given by the fastest step

A cubic solid is made of two elements P and Q Atoms of Q are at corners and face centres of the cube and P at all octahedral voids then the coordination numbers of P and Q respectively are 4 and 4 1 and 1 8 and 8 6 and 6

The cubic unit cell structure of a compound containing cation M and anion X is shown below When compared to the anion the cation has smaller ionic radius Choose the correct statement s Ox A The empirical formula of the compound is MX B The cation M and anion X have different coordination geometries C The ratio of M X bond length to the cubic unit cell edge length is 0 866 D The ratio of the ionic radii of cation M to anion X is 0 414 M

A Among the following species identify the isostructural pairs NF3 NO3 BF3 H3O HN3 1 NF3 NO3 and BF3 H3O 2 NF3 HN3 and NO3 BF3 3 NF3 H3O and NO3 BF3 4 NF3 H3O and HN3 BF3

nm is incident on it The work function of sodium is 2 28 eV b Calculate the value of the longest wavelength which can result in the emission of a photoelectron from a sodium surface Ultraviolet light of wavelength 280 nm is used in an experiment of photoelectric effect with lithium w 2 5 eV cathode Find

For the chemical reaction 2 HI g H g 1 g The incorrect option is O 1 1 d HI d H 2 dt dt O 1d HI d 2 dt d HI dt d H d dt dt dt 1 d H 2 dt

For a reaction A B C AH 40 kcal mol If Ea for the forward reaction is 30 kcal mol then E for the backward reaction is O 100 kcal mol O 50 kcal mol O 70 kcal mol 40 kcal mol

When electromagnetic radiation of wavelength 300 nm falls on the suface of sodium electrons are emitted wi a kinetic energy of 1 68 x 105 J mol What is the minimum energy needed to remove an electron fro sodium What is the maximum wavelength that will cause a photoelectron to be emitted A 908 nm B 517 nm C 1010 nm D 205 nm

B 517 nm C 1010 nm D 205 nm The thereshold frequency vo for a metal for a metal is 7 0 x 10 4 s Calculate the kinetic energy of an elee emitted when radiation of frequency v 1 0 x 10 5 s 1 hits the metal

In 12 gm of mono basic organic acid 4 8 gm carbon 0 8 gm hydrogen and 6 4 gm oxygen present 0 8 gm of silver salt of same monobasic organic acid left a residue of 0 5175 gm of silver on ignition The molar mass of acid is O 59 O 60 O 39 10

8 The activation energy of a first order reaction at 27 C is 54 kJ mol In the presence of a catalyst the activation energy of the same reaction lowers to 44 kJ mol at 27 C How many times the reaction rate changes in the presence of a catalyst at 27 C 9 The specific rate constant for the reaction of H with I to form HI is 0 43 at 673 K If the activation energy is 171 5 kJ mol what is the rate constant at 773 K

Given aA g bB g cC g dD g which is are correct statements 1 Vapour density of gaseous mixture increase if a b c d Molar mass of gaseous mxture decrease of a b c d Relative density of gaseous mixture w r t He is constant dung progress of reation if a b c Total mass remains constant during progress of reaction when a b c d

In electrochemistry chapter under the topic electrolysis w ith same type of electrode sir said that on electrolysis of FeSO4 we will get Fe at cathode and Fe at anode But reduction potential of Fe is smaller than H then wh y this will happen at cathode

Pre Medical Chemistry Given below are the half cell reactions Mn 2e Mn E 1 18 V 2 Mn e Mn E 1 51 V The Eo for 3Mn Mn 2Mn3 will be 1 0 33 V the reaction will not occur 2 0 33 V the reaction will occur 3 2 69 V the reaction will not occur 4 2 69 V the reaction will occur ut Explain full question ow Mainly explain how we get n 2 for resultant reaction

Please explain in detail what is levelling effect and what i s levelling solvent Also do we have to learn the relative strength of different acids o auto n Any substance such as water which may function as an acid as well a base is called amphoteric Strength of all strong acids HCI H SO HNO HCIO etc in water is same and become equal to the strength of H O ion This is called levelling effect of water So strength of strong acids is compared in glacial acetic acid Water is called levelling solvent and glacial acetic acid is called differentiating solvent for strong acids Levelling effect of water is due to its high dielectric constant and strong tendency to accept protons Strength of all strong bases in water is the same and becomes equal to the strength of OH ion because of levelling effect of water Any acid having acid constant K greater than 1 may be regarded as strong acid Relative strength of acids in glacial acetic acid follows the order HCIO HI HBr H SO HCI HNO H O H PO HF CH COOH H CO H S HCN The strongest acid known is HCIO and strongest base known is CSOH

Consider the following statements for lead storage battery a It consists of a grid of lead packed with PbO2 as anode and a lead cathode b 38 solution of H SO4 is used as an electrolyte c It is commonly used in automobiles and invertors Which of the above statements are correct O a and c Ob and c O a and b

0 ml of 2M CaCl solution is mixed with 60 ml of AICI3 solution and the mixture is diluted to 500 ml If the diluted solution contains 0 7 moles chloride ions the molarity in mol litre of AlCl3 solution usec

Select an incorrect statement among the following O Solubility depends on the nature of solute and solvent O Solubility of a gases in liquid increases with decrease of temperature O Aquatic species are more comfortable in warm waters than in cold waters O Higher the value of KH the lower is the solubility of the gas in the liquid

An ionic solid A Be crystallizes as a bc structure The distance between cation and anior in the lattice is 338 pm Calculate the edge length of the unit cell 1 195 15 pm 2 97 58 pm 3 390 3 pm

If rate constant for a first order reaction is 60 s then how much time will take to reduce the initial concentration of the 1 16 reactant to its th value 2 3 10 2 s 4 6 x 10 s 6 9 x 10 s 1 2 x 10 2