Physical Chemistry Questions

c d 10 12 87 The toxic compound 2 4 dinitrophenol has K 104 In an experiment a buffer solution of 2 4 dinitrophenol was prepared with the pH adjusted to 5 Calculate the ratio of th concentrations of the dissociated ion to the undissociated acid a 0 01 b 0 1 c 10 d 100 88 Equilibrium constant for the followi

A 2B C follows 1st order kinetics The reaction is started with pure A in a rigid closed vessel maintained at constant temperature After 10 sec a pin hole is developed in the vessel If the molar ratio of gases A B coming out initially is 1 2 find the rate constant of the reaction in sec1 MA 16 MB 4 Mc 8

SolveLancer Test When 0 14 L of a mixture of nitrogen and hydrogen are mixed 0 002 L of nitrogen remained The initial mixture contains by volume SolveLancer Test a 26 N b 20 N X 5609 c 34 N d 3 4 N

71 The enthalpy of neutralisation of four acids HA HB HC and HD with NaOH are 13 12 11 10 kcal mol Which salt has maximum degree of hydrolysis a 1M NaA b 1M NaB c 1M NaC 35 1M NaD ml of weak arid HA

a 1M NaA b 1M NaB c 1M NaC 72 Calculate H at equivalent point between titration of 0 1 M 25 mL of weak acid HA Ka HA 10 5 with 0 05 M NaOH solution b 1 732 x 10 a 3 10 c 8 d 10 3 When a salt of weak and and work baco is dissolved in water at 25 C the pH of the resultin

79 Calculate the pH at 25 C of a solution that is 0 10 M in Fe NO3 3 The acid dissociatio constant for the reaction given below is 1 0 x 10 3 Fe H O 6 H O l b 2 02 a 2 00 H3O aq Fe H O 5 OH c 2 30 d 2 50

Consider the following reaction A forward backward B The forward rate constant of the above reaction increases by 100 when its temperature is raised from 290 K to 300 K while its equilibrium constant is decreases by 50 Identify the correct statement s Energy of activation for the forward reaction is 17 4 x In2 kcal Energy of activation for the backward reaction is 8 8 x ln2 kcal The magnitude of standard heat of reaction is 17 4 In2 kcal Overall the given reaction is exothermic

Equal mass of a solute are dissolved in equal mass of two solvents A and B and formed very dilute solution The relative lowering of vapour pressure for the solution B has twice the relative lowering of vapour pressure for solution A If MA and MB are the molecular masses of MA MB MB 2MA MA 4MB

2 A catalyst lower the activation energy by 5 75 kJ mol at 27 C the rate of the reaction will increase by 1 2 times of its original rate 2 5 times of its original rate 3 10 times of its original rate 4 12 times of its original rate

7 What is the hydronium ion concentration of a 0 02 M solution of Cu2 solution of copper II perchlorate The acidity constant of the following reaction is 5 10 9 Cu OH aq H3O aq c 5 x 10 4 a 1x 10 5 2 Cu aq 2H O 1 b 7 10 4 d 1x 10 4

5 6 The empirical formula of a gaseous compound is CH The density of the compound is 1 25 gm lit at S T P The molecular formula of the compound is X 1 C H 2 C HS 3 CH 4 CH The density of water is 1 gm ml The volume of water drop is 1 8 ml The no of molecules A

2 For a first order reaction following data is collected A g B g C g Time 0 20 min Total pressure 60 105 The half life of the reaction is 1 5 min 3 20 min 3 2 10 min 4 40 min Classification based on physical states solid

3 2 bond pairs and 3 lone pairs 4 Both 1 and 3 52 A container contains mixture of O2 and H2 If 1 mole fraction of H2 is then the ratio of volume 3 of H to O2 diffuse out initially from the container is 1 1 2 3 1 1 2 2 1 4 4 1

c be less than 7 depend upon Ka and K value 74 What will be the pH of an aqueous solution of 1 0 M ammonium formate Given pK 3 8 and pK 4 8 a b a 7 5 b 3 4 c 6 5 d 10 2 5 What will be the pH and a degree of hydrolysis respectively for the salt 6 10 concentrati TT DOTT 6

For adsorption of gas over solid surfac following data is obtained at 300 K 100 Pressure of gas mm of Hg Amount adsorged per kg of charcoal 3 gm 25 1 5 gm The slope of the graph between log P vs log x m will be x m and P are in same units as given 2linu 3 loups question

1 mole of an ideal gas initially present in a 2L insulated cylinder at 300 K is allowed to expand against vaccum to 8 L then IAGsysl in calories will be In2 0 7 Correct Answer 840 00 our Answer 830 tatus incorrect

Example 19 The emf of the cells obtained by combining zinc and copper electrodes of the Daniell cell with calomel electrodes are 1 083 volt and 0 018 volt respectively at 25 C If the reduction potential of normal calomel electrode is 0 28 volt find the emf of the Daniell cell

78 What is the acidity constant for the following reaction given that the hydronium ion of a 0 04 M solution of Ni2 solution of nickel II perchlorate is 4 5 10 concentration Ni 2 aq 2H O l b 4x10 6 70 a 2x10 12 Calculate the IT rec of leati Ni OH aq H3O aq c 5 x 10 12 in 0 10 Min Fa NO 5x10 10 The s 1 dissociati

2 54 A solution is prepared by mixing 250 ml toluene C Hg and 8 4 g thiophene C H4S Then molality of thiophene in the solution is Given Density of toluene 0 8 g ml Density of thiophene 1 2 g ml Multiply your answer by 10

Consider the statements and select the incorrect one Bromine oxides BrO and BrO3 exist only at low temperature lodine oxides 1205 and 1207 are insoluble solids and decompose on heating The stability of oxides formed by I Cl and Br follow the order I Br Cl The higher oxides of halogens are more stable than the lower ones

6 For the reaction A g 2B g Kp 8 atm if initially 4 atm of gas A is present then total pressure at equilibrium is 1 2 atm 3 6 atm 2 4 atm 4 8 atm

Due to some accident a radioactive element spread over the laboratory its activity is found to be 10 times the permissible value The mean life of the radioactive element is 200 hours After how many days the room will be available for safe working 10 days 15 days 8 days 19 days

Match Column I with Column II Column I Q1 A B C r K A Q2 A B C 2D r K A B B Q3 A 2B C D r K A B Q4 2A BC Dr K A B Q1 03 A1 A2 A3 A4 A5 Column II A1 The rate of consumption of both the reactants is equal A2 Unit of rate constant is equal to 1 mol time A3 Rate of consumption of one of the reactant is twice of rate of formation of one of the product A4 t1 2 of both the reactants is equal if equal concentration is taken A5 t1 2 of one of the reactant is twice to that of the other reactant if equals concentration is taken

33 Given the following nine aqueous solutions 1M CH COOH 0 5M NaOH 3 w v Glucose 1 2 3 0 2M NaCl 6 Centimolar sucrose 7 E 0 2M Urea 4 Decimolar H C O4 8 4 w v NaOH 5 0 9 w v Na CO3 9 Select correct option s A Solution 7 has minimum g L of solute B Only two solutions have same g L of solute C On dividing by ten in four solutions g L of solute value is whole number

Divide your answer by 10 60 Enthalpy for the reaction Ag aq Br aq AgBr s is 90 kJ Magnitude of enthalpy of formation of Ag aq and Br aq are in the ratio 5 6 Formation of Ag aq is an endothermic process whereas formation of Br is an exothermic process Enthalpy of formation of AgBr is 110 kJ mol The enthalpy of formation of Ag aq will be kJ mol

Column I Process P AS surrounding 0 Q AS surrounding 0 PS C Adiabatic free expansion Pext 0 of R ASS surrounding an ideal gas P A Reversible isothermal ideal gas expan sion Q B Reversible adiabatic ideal gas com pression D Irreversible isothermal ideal gas com D S AS Entropy change system 0 0

Kn 28 Balmer gave an equation for wavelength of visible region of H spectrum as 2 4 Where n principal quantum number of energy level K constant in terms of R Rydberg constant The value of K in terms of R is R a R b 2 4 R d 5 R IG 1

If density of a gaseous mixture of dinitrogen tetroxide N O4 and nitrogen dioxide NO is 2 5 gm L at 127 C and 1 atm pressure R 0 08 atm lit mole K 2 13 Partial pressure of N O is A 0 62 atm B 0 47 atm 2 14 Kp for N O4 g 2NO is A 0 90 B 0 09 C 0 74 atm C 9 0 D 0 26 atm D 0 009

Assertion A Hmix and AVmix are zero for the ideal solution Reason The interactions between the particles of the components of a solution are almost identical between particles in the pure liquids

PT P PA B PB 1 Z X Y 0 X Mole fraction of liquid A in liquid solution Y Mole fraction of vapour A in vapour mixture Z is the graphical mid point between 1 X Find value of P Y Given PT 450 mm Hg 100X If P A 300 mm of Hg no 700

0 16 Arrange the following in the decreasing order of covalent bond length C C C N C H O H Options 11 22 13 0 17 LCCaC KH of C C C H C N O H 3 0 C C H C C C N 4 C N C C O H C H 1 Select the correct option for elements in the increasing order of I ionizanion euthalpy Ph So G S

16 gm of sulphur is burnt to form SO2 which is oxidised by Cl water The solution is then treated with BaCl solution The amount of BaSO4 precipitated would be b 0 5 mole a 1 mole c 0 24 mole d 0 25 mole 100 gm mixture on Na2CO3 and CaCO3 was heated until 5 6 litre of CO2 gas was collected at NTP What is the mass percentage of CaCO3 in the mixture

141 The variation of radial probability density R2 r as a function of distance r of the electron from the nucleus for 3 p orbital a R2 r b R2 r c R r R2 1

o felectron 9 10 kg ty of light 3 x 10 ms 1 s constant 6 626 x 10 34 Js of electron 1 6 10 19 jeV 1 0 9eV 3 1eV 2 1eV 2 1eV 21791 581 hc 1 2mv 2 34 6 626 X10 X 3X10 2 x 9 1X103 X 6 105 X 4000 X1070 32995804 what is the work fuction of the metal if the light of wavelength 4000 generates photoelectrons of velocity 6 105 ms from JEE Mains 2019 12 January Shift 1 it 31 Mass o felectron 9 10 kg Velocity of light 3 108ms 1 Planck s constant 6 626 10 34 Js Charge of electron 1 6 10 19 je V 1 1 2 d doubtnu 62801 Watch Later What will be the workings of the metal if 4000 AWavelength light 6 105 m Produces photoelectrons of velocity 1 31 1 34 Electron code 9 10 kg velocity of light 3 10 ms Planck constant 6 626 X 10 Js and the charge of electron 1 6 x 10 1 JeV 000

Electrochemistry I Electrolysis of water 3 Questions 1 During electrolysis of water volume ratio of H to O gases obtained is 1 1 2 2 1 3 3 2 1 4 3 1

The following data were obtained at a constant volume for the decomposition of di tertbutyl peroxide in the homogenous gas phase at 500 K t min 0 10 20 P torr 200 250 290 The reaction is as following first order kinetics CH3 3 COOC CH 2CH COCH C H6 log 8 7 0 058 log 40 31 0 115 Identify the correct statement s C H6 At time equal to 10 min the pressure due to C H6 is 50 torr The rate constant is approximately equal to 1 33 10 min 1 At time equal to 20 min the pressure due to acetone is 90 torr The rato constant is ximatoly oqual to 0 8 x hr 1

Example 14 The standard reduction potential for the half cell having reaction NO3 aq 2H aq e NO g H O is 0 78 volt i Calculate the reduction potential in 8 M H ii What will be the reduction potential of the half cell in a eutral solution

One mole of an ideal monoatomic gas is taken from state A to state B through the process 1 T It is found that its temperature increases by 115 2 K in this process Now it is taken P 3 2 from state B to C through a process for which internal energy is related to volume as U The volume at B is 100 m and at C it is 1600 m then the total work done by the gas is ax 10 2 Then the value of a is R 25 3 J mol K

2 51 For a chemical reaction starting with some initial concentration of reactant A as a function of time t is given by the equation 2 1 5 x 10 t 1 Af The rate of disappearance of A is x 102 M sec when A 2 M Given A in M and t in sec Express your answer in terms of 102 M s Round off your answer if required

When the electric current is passed through a cell having an electrolyte the positive ions move towards cathode and negative ions towards the anode If the cathode is pulled out of the solution then The positive and negative ions will move towards anode The positive ions will start moving towards the anode while negative ions will stop moving You marked The negative ions will continue to move towards anode while positive ions will stop moving The positive and negative ions will start moving randomly

Problem1 If N gas is bubbled through water at 293 K how many millimoles of N dissolve in 1 litre of water Assume that N exerts a partial pressure of 0 987 bar Given that Henry s law constant for N at 293 K is 76 48 kbar NCERT Solved Example 097 har

Calculate the probability that no triple among n random 32 bit integers sums to 0 and give an approximate estimate for n equal to 1000 2000 and 4000 Give an approximate formula for the expected number of such triples as a function of n and run experiments to validate your estimate

the reaction was carried out at 150 C with a mixture of solvent and catalyst 10 moles of glycerol and 7 3 moles of KOH per mole of eugenol the conversion of eugenol reached 99 after the reaction lasted 3 hours Based on these data KOH 4 4 mol estimate the order of the reaction for the KOH catalyt and Ea 94 5 kj mol

1 A galvanic cell is formed by combining Zn rod immersed in Zinc chloride solution of concentration 0 6M and Mg rod immersed in Magnesium chloride solution of concentration 0 15M Write cell representation cell reaction and calculate EMF of cell at 25 C given the Standard reduction potentials of Mg and Zn electrodes as 2 36 and 0 76V respectively

3 26 H Partial pressure needed to dissolve 21 mg of CO in 100 gr of water at 298K is K for Co KPa m mol 2 3 a 14 KPa b 7 KPa c 121 KPa d 79 KPa ELITE SERIES for Sri Chaitanya Sr ICON

A piece of lead of mass 1 kg at 50 C is placed in a copper container of mass 50 g containing 200 g of liquid X at 20 C If the final temperature of the system is 30 C predicting the specific heat capacity of the liquid X Given that the specific heat for copper and lead are 390 J kg C and 130 J kg C 1 respectively

3 Consider the reaction Pb OH 4 2 aq Sn OH 4 2 aq Pb Sn OH 6 2 aq 2OH aq If equal moles of both Pb OH 4 2 and Sn OH 6 2 are initially present in its aqueous solution then after reaction 1 Vapour pressure of solution increases 2 Van t Hoff factor decreases 3 Boiling point of solution increases 4 Freezing poiont of solution increases

For the given equilibrium ENOCI g 2NO g Cl g The value of the equilibrium constant Ke at 100 K is 3 x 10 The value of K for the satur reaction at 1000 K is 10 25 2 0 025 3 2 5 4 25 HGEO03 Question Type MCQ Question 10 190012 Optu 110 1902885 Option 210 15000 Option 310 15000 Op 01900091 States Answered Chosen Oefen 1

At a temperature of 30 C hexane is dissolved in water at a mole fraction of 0 67 x 10 6 At this temperature the solubility of hexane in water is xsat 10 6 What is the vapor pressure of pure hexane at 30 C if the fugacity of hexane in the gas phase is equal to 0 5 bar

m 1 d 2 a 4 1 1 How ma d 4p 6 tron which is rem 0 ms 1 173 Wave function of an orbital is plotted against the distance from nucleus The graphical representation is of a 1s b 2s R c 3s d 2p