Physical Chemistry Questions

straight line is obtained The points at which the line When a graph between log k and 1 T is drawn a cuts y axis and x axis respectively correspond to the temperatures 1 0 E 2 303R logA JogA 2 E R in A 4 log A

A mixture of CH4 and C2H occupied a certain volume at a total pressure of 63mm The sample was burnt to CO2 and H O and the CO2 alone was collected and its pressure was found to be 69mm in the same volume and at the same temperature as the original mixture What is the contribution of Ethyne in percentage in the mixture A 90 4 B 80 6 C 26 5

In an electrolysis experiment current was passed for 3 hour through two cells connected in series The first cell contains a solution of gold and second contains CuSO4 solution 5 2g of gold was deposited in the first cell If the oxidation number of gold is 3 the amount of Cu deposited on the cathode and the magnitude of the current in ampere are respectively 1F 96500 coulomb Au 197 A 4 76g 0 8 Ampere B 9 74g 1 Ampere C 5 5g 0 5 Ampere D 2 5g 0 7 Ampere

2 012 1020 photons per second Example 11 Calculate the maximum kinetic energy of photoelectrons emitted when a light of frequen 2 x 1016 Hz is irradiated on a metal surface with threshold frequency v equal to 8 68 x 1015 H olution hv hvo KE Threshold frequency vo 8 68 x 1015 Hz s Frequency of light v 2 1016 Hz KE h v v 6 626 10 34 2 x 1016 8 68 x 10 5 KE 7 5 x 10 18 J Maximum kinetic energy of photoelectrons 7 5 10 18 J

2Ca s O2 g 2CaO s AHorxn 1269 8 kJ ASorxn 364 6 J K For this problem assume that all reactants and products are in their standard states Calculate the free energy change for the reaction at 29 C

The osmotic pressure shown by 0 1 molar aqueous solution of a weak electrolyte AB is 3 6 atm 300 K Find dissociation of weak electrolyte AB Use R 0 08 L atm K mole Sum the digits of your answer till you get single digit number

51 A mixture of HCOOH and H C2O4 is heated with concentrated H SO4 The gas produced is collected and on treating with KOH solution the volume of gas decreases by one sixth Calculate the molar ratio of the two acids HCOOH H2C2O4 in the original mixture

Following is the list of four halides Select correct sequence of increasing order of reactivity for SN reaction using the codes given below 1 C6H5 CH Br CH3 11 C6H5 CH Br III C6H5 CHI CH3 IV C6H5 CH I A 11 IV B IV II III C II IV I

d 3 14 mho cm 4 4 The resistance of 0 01 N solution of an electrolyte was found to be 210 ohm at 298 K using a conductivity cell of cell constant 0 66 cm The equivalent conductivity of solution is a 314 28 mhocm eq 1 b 3 14 mho cm eq 1 cm eq 1 c 314 28 mho cm eq d 3 14 mho 1 If the electrolyte used in problem 4 is Ba NO3 2 then

27 a Be and Mg are alkaline earth metal b K have larger radii than Ca c All d block elements are transition elements d He ion have larger size than F Znis Incorrect statements is are 1 a c d 3 a d 2 b c 4 a c

EXAMPLE 2 5 Liquids A and B form an ideal mixture in which the mole fraction of A is 0 25 At temperature T a small quantity of the vapour in equilibrium with the liquid is collected and condensed This process is repeated for a second time with the first condensate The second condensate now contains 0 645 mole fraction of A Calculate the ratio PA PB What will be the mole fraction of B in the third condensate

Two half reactions of an electrochemical cell are given below MnO4 aq 8H aq 5e Mn2 aq 4H O 1 E 1 51 V Sn aq Sn4 aq 2e E 0 15 V Construct the redox reaction equation from the two half reactions and calculate the cell potential from the standard potentials and predict if the reaction is reactant or product favoured All India 2010

If a copper rod free to move and rotate is brought in a region of a non uniform magnetic field then it will align itself 1 Along the direction of the magnetic field at a location where the magnetic field is strongest 2 along the direction of the magnetic field at a location where the magnetic field is weakest 3 perpendicular to the direction of the magnetic field at a location where the magnetic field is strongest 4 perpendicular to the direction of the magnetic field at a location where the magnetic field is weakest In a marriage hall there are 15 bulbs of 45 W 15 bulbs of 100 W 15 small fans of 10W and 2 heaters of 1 kW If the voltage of the electric main is 220 V then the minimum fuse capacity in A

The best procedure to use when filtering an aqueous solution to collect the precipitate is to Suball coal pl Wash the precipitate with a minimal amount of water Not wash the precipitate at all Use large volumes of water to ensure that all soluble matter is separated from the precipitate Warm the solution before filtering

20 Read the following and answer any four questions In the electrolytic refining of copper The electrolyte is a solution of acidified copper sulphate There are an anode and cathode Refining is carried out by passing an electric current Cathode 52 Cu a Anode i The anode is a pure strips b impure copper c refined copper d none of these ii Anode mud consists of a insoluble impurities b soluble impurities Acidified copper sulphate Impurities Ganode mudi c pure metal d impure metal iii Which of the following are refined electrolytically A Au B Cu C Zn D K a A and B b B and C c A B and C d B C and D iv On passing electric current Cu is deposited on a cathode b anode c bottom of cathode d bottom of anode v Which one of the following four metal would be displaced from the solutic

The reaction 2A B C D goes to completion and follows the rate law d B dt K A B Calculate the values of x y in the following data Set A x 10 3 M Bo 10 M 1 300 2 300 3 5 10 A 375 C 385 4 16 300 300 Half life sec 62 5 625 B 380 D 390

3 36 32 10 ml of HCI 30 ml of HNO3 75 ml of 2 N 5 4 48 N 10 H SO4 are mixed together The normality a resulting solution is 1 0 02 N 2 0 5 N 3 0 2 N 4 0 025 N 33 A solution of NaOH is 4 g L 1 What volume of H L CTD will noutralize 50 ml of the al

5 In three beakers labelled as A B and C 100 mL of water 100 mL of 1M solution of glucose in water and 100 mL of 0 5 M solution of glucose in water are taken respectively and kept at same temperature water 1 M glucose solution 0 5 M glucose solution B Which of the following statements is correct C a Vapour pressure in all the three beakers is same b Vapour pressure of beaker B is highest c Vapour pressure of beaker C is highest d Vapour pressure of beaker B is lower than that of C and f hooker C is lower than that of A

c Surface tension 31 The molecular conductivity and equivalent conductiv are same for the solution of a 1 M NaCl c 1 MLa NO3 3 ativity is b 1 M Ba NO3 2 d 1 M Th NO3 4

palielam com excams review 64409 unanswered basic 21 You are provided with 1 mol each of nitric acid HNO sulphuric acid H SO and perchloric acid HCIO respectively in beakers A B and C Select the correct option from the following Atomic mass of N 14u S 32u C1 35 5u 1 A 2 A 3 A 4 A B B B B C

33 a Calculate the maximum work and log Kc for the given reaction at 298 K Ni s 2Ag aq Ni aq 2Ag s Given E Ni2 Ni 0 25V EAg Ag 0 80 V 1F 96500 C mol 7 b On the basis of E values identify which amongst the following is the strongest oxidising agent and why Ch g 2 e 2CI E 1 36 V Mr out fot Mn 14 0 Co 1 51Y 3 2

57 Which one is the most likely structure of CrCl 6H O if 1 3 of total chlorine of the compound is precipitated by adding AgNO to its aqueous solution 1 CrC1 6H 0 3 CrCL H O C2H O 2 Cr H O CI 3H O 4 CCI H O CL H O

The vapour pressure of a 5 aqueous solution of a non volatile organic substance at 373 K is 745 mm Calculate the molecular mass of the solute

In a particular chemical reaction at 500 C and 1 atm pressure in the presence of catalyst V 205 the energy released is 182 kJ We can say about this reaction that it is a an O O exothermic reaction endothermic reaction neither exothermic reaction nor endothermic reaction data insufficient

Consider the following statements a NO2 is an odd electron molecule b 03 molecule has two resonating structures c PF5 follows octet rule The correct statements is are a and b only b and c only a and c only a b and c

The depression in freezing point of 0 01 M aqueous solutions of urea sodium chloride and sodium sulphate is in the ratio of Roorkee 1990 DCE 1994 1 1 1 1 2 1 2 3 3 1 2 4 4 2 2 3 2 86 From NCERT 3

If an antacid tablet releases 1 g of CO2 molar mass 44g mol What is the mass of NaHCO3 Molar mass 84g mol that is found in the tablet HCO3 aq H aq CO2 g H2O l 3 5 g O1 91 g 1 51 g

4 g of solid NaOH was dissolved in water and the solution was made up to 1000 ml The whole of this will neutralized completely 1 100 ml of 1 M H SO4 M H SO4 ho 2 20 ml of 2 5 M H SO4 3 20 ml of 1 5 M H SO4 4 30 ml of 5 M H SO4 08

In the Rutherford Gold foil experiment he bombarded alpha par ticle i e He nuclei He2 ion which contained 2protons and 2neutrons on a gold foil through which he acknowledged that most of the part of atom is empty and the mass is situated at nucleus of atom But when the He2 nuclei was bombarded it passed through the gold foil atoms which also contained elec trons so why the electrons didn t attracted the protons of the He2 ion instead it got scattered by different angles Because the protons of He2 nuclei and electrons of gold foil are of opposite charges and opposite charges attract each other

Which of the following does not indicate a high level of pollutants or toxic substances 1 High DO value III High BOD value O O I II and III only II and IV only O II and III only III and IV only II High COD value IV High TLV

A gas phase recombination reaction is first order in each of the reactants The energy of activation for the reaction is 49 6 kJ mol At 55 C the rate constant is 0 23 m s1 Calculate the entropy of activation at 55 C Select one a 79 J K 1 mol 1 b 87 J K 1 mol 1 Oc 112 J K 1 mol 1 O d 78 J K 1 mol 1 e 93 J K 1 mol 1

Consider the combustion of liquid methanol CH OH 1 O2 g CO g 2H O l AH 726 5 kJ If the reaction were written to produce H O g instead of H O l the magnitude of AH increase decrease O remain unchanged O can t be predicted

Calculate the quantity of energy produced per gram of reactant for the fusion of H 3 atomic mass 3 016049 amu with H 1 atomic mass 1 007825 amu to form He 4 atomic mass 4 002603 amu Express your answer using five significant figures WAZ Pa G P C ww 2

The combustion of octane C8H18 proceeds according to the reaction shown 2C8H18 1 25O2 g 16CO2 g 18H2O l If 4 90 102 mol of octane combusts what volume of carbon dioxide is produced at 16 0 C and 0 995 atm

1 mass 2 volume 3 surface tension Xenthalpy Out of boiling point I entropy II pH III and e m f of a cell V intensive properties are 1 I II 2 I II III LOT I III IV librium involves 4 All of the above

Complete combustion of 1 80 g of an oxygen containing compound C H O gave 2 64 g of CO and 1 08 g of H O The percentage of oxygen in the organic compound is 1 51 63 2 63 53 3 53 33 4 50 33

Identify which of the following is correct about the below given reaction 2 H O g 2 H2 g O2 g At low temperature the reaction is nonspontaneous and AG 0 and at high temperature the reaction is nonspontaneous and AG 0 At low temperature the reaction is nonspontaneous and AG 0 and at high temperature the reaction is spontaneous and AG 0 At low temperature the reaction is spontaneous and AG 0 and at high temperature the reaction is nonspontaneous and AG 0 O At low temperature the reaction is spontaneous and AG 0 and at high temperature the reaction is spontaneous and AG 0 O It is not possible to determine without more information

If dipole moment of AB molecule is 1 6 10 2 Cm and distance of A B bond is 1 6 then percentage ionic character of the compound will be 62 5 75 1 70 5

sion and Absorption Spectra The spectrum of radiation emitted by a substance that has absorbed energy is called an emission spectrum Atoms molecules or ions that have absorbed radiation are said to be excited To produce an emission spectrum energy is supplied to a sample by heating it or irradiating it and the wavelength or frequency of the radiation emitted as the sample gives up the absorbed energy is recorded An absorption spectrum is like the photographic negative of an emission spectrum A continuum of radiation is passed through a sample which absorbs radiation of certain wavelengths The missing wavelength which corresponds to the radiation absorbed by the matter leave dark spaces in the l

1 For the reaction given below a 1 0 L container initially contained 3 0 mol L of A g and 2 0 mol L of B g 2A g B g C g At equilibrium the concentration of C g is 0 75 mol L What is the concentration of A g

A substance A undergoes disproportionation reaction to form A and A obeying first order kinetics The rate constant is obtained by measuring volume of an oxidizing agent capable of oxidizing A A and A to A A A respectively From the following data calculate moles of A 6 minutes after starts of the reaction if initially 10 moles of A was taken Round off to nearest integer Time min Volume of oxidizing 20 21 5 r agent 0 4 min ml

A closed cylinder contains 20 g helium gas and 64 g oxygen gas exerting a pressure of 10 atm Partial pressure of oxygen in the cylinder is 3 21 atm 2 86 atm 4 45 atm

1 Calculate the concentration of Cu lon for an electrochemical cell consisting of different components of copper and Turkey in a CuSO4 solution Concentration and from an elevated electrode of silver dipped in an AgCl solution deepening of its height M 0 02 Note the output voltage of the search for a source 0 412 V and using our help In the following equations Ag aq e Ag s Eo 0 799 V Cu2 aq 2 e Cu s Eo 0 337 eV

Normal blood sugar level CHO in an adult human is 7mmolL If the blood sample of a contains 2000mg L then person 1 The person is non diabatic 2 The person is diabetic 3 Not enough information 4 None of the above

When a liquid molecular mass 378 that is immiscible with water was steam distilled at 95 C at a total pressure of 750 torr the distillate contained x gm of liquid per gm of water Calculate the value of x Where vapour pressure of water is 630 torr at 95 C

In an electron microscope electrons are accelerated to great velocities Calculate the wavelength of an electron travelling with a velocity of 7 0 megameters per second The mass of an electron is 9 1 x 10 31 kg A 1 0 x 10 13 m B 10x107m C 10 m

During the titration of 20mL of x M NaOH using standard solution of HC1 of molarity 0 1M the pink colour of phenolphthalein changes to colourless on the addition of 19 8mL HCl solution Then the value of x is 1 0 1 2 0 098 3 0 099 4 0 001

38 If the ionization energy of He is 19 6 10 18 J per atom then the energy of Be3 ion in x 34 second stationary state is a 4 9 x 10 18 J The energy of the second Rohr orbi in the br b 44 1x 10 18 J c 11 025 x 10 18 J d None of these

2 0 g sample contain mixture of SiO2 and Fe2 O3 on very strong heating leave a residue weighing 1 96 g The reaction responsible for loss of weight is Fe2 O3 s Fe3 04 s O2 g unbalance equation What is the percentage by mass of SiO2 in original sample 1 10 2 20 3 40 4 60

fo H H C CH3 aq alkaline KMnO A Which one of the following is true about this reaction 1 A is meso 2 3 butanediol formed by syn addition 2 A is meso 2 3 butanediol formed by anti addition 3 A is a racemic mixture of d and I 2 3 butanediol formed by anti addition 4 A is a racemic mixture of d and I 2 3 butanediol formed by syn addition