Physical Chemistry Questions

15 If potential of the cell is 0 98 V at 25 C Then calculate the pH in anodic compartment Pt s H 1 atm H aq Agt 0 1 M Ag s Given E Ag Ag 0 8 V and 2 303RT F 0 06

equilibria is 1 1 36 2 1 1 3 1 3 4 1 9 4 A vessel at 1000 K contains CO with a pressure of 0 5 atm Some of the CO is converted into CO on the addition of graphite If the total pressure at equilibrium is 0 8 atm the value of K is AIEEE 2011 1 0 3 atm 4 3 atm 2NO g at temperature T is 2 0 18 atm 3 1 8 atm 5 The equilibrium constant Kc for the reaction N g O2 g

4 The ratio of masses of oxygen and nitrogen in particular gaseous mixture is 1 4 The ratio o number of their molecule is JEE Mains 2014 a 1 4 b 7 32 d 3 16

21 Consider the following reaction 2 Z xMnO4 yC 02 zH xMn 2yCO H 2 The values of x y and z in the reaction JEE Mains 201 respectively a 2 5 and 8 c 5 2 and 8 b 2 5 and 16 d 5 2 and 16

A 9 B Between 6 and 7 C 7 14 8 gm NaOH and 4 9 gm H SO4 are present in one litre of the solution What is its pH A 1 B 13 C 12 D 2 D 4 0 g What is the quantity of NaOH present in 250 cc of the solution so that it gives a pH 13

11 In what pH range will a 1 x 10 4 M solution of an indicator will K indicator 1 x 10 change colour A 7 0 1 B 3 0 1 C 5 5 1 D 11 0 1 K 10x10 5 The acid form of the indicator is red and the basic She

Heat of atomisation of NH and N H are x kcal mol and y kcal mot respectively Calculate average bond energy of N N bond 4y 3x 1 kcal mol 2 2y 3x kcal mol 3 4y 3x 4 3y 4x kcal mol 4 3 kcal mol 1

50 mL of 0 1 M NaOH is added to 75 mL of 0 1 M NH CI to make a basic buffer If pK of NH is 9 26 calculate pH Lof 12 Moolution of pyridine CH N K 15x10 9

A chemical compound dioxin has been very much in the news in the past few years It is the by produc of herbicide manufacture and is thought to be quite toxic Its formula is C 2H4Cl O2 If you have a sample dirt 28 3 g that contains 8 78 x 10 8 moles of dioxin calculate the percentage of dioxin in the dirt sample ant Academy 1 Pvt Ltd B 41 Road No 2 IPIA Kota Raj Ph 06377791915 www vibrantacademy com 15

Write cell representation for following cells Cd aq Zn s Zn aq Cd s 6 2Ag aq H g 2H aq 2Ag s 2 c Cr 0 a 14H aq 6Fe2 aq 6Fe aq 2Cr aq 71 da ndard electrode potential

D Henry law constant of N in water is 104 atm Find the molality Approx of N in water when pressure of N over water surface is 5 atm consider 2 temperature remains constant 1 0 10 2 0 028 3 0 05 4 0 12

What is the value of n in the following equation Cr OH OH CrO2 H O ne 4 1 3 3 5 2 6 4 2

For combustion of 1 mole of benzene at 25 C the heat of reaction at constant pressure is 780 9 kcal What will be the heat of reaction at constant volume CH6 1 72 02 g 6CO2 g 3H O 1 a 781 8 kcal c 781 8 kcal b 780 0 kcal d 780 0 kcal

What weight of 75 0 NaOH by weight must be dissolved in water to prepare 250 mL of 1 50 M NaOH FW 40 0 A 20 0 g C 11 2 g D 5 33 g B 15 0 g SECTION MATRIY

A metal M of atomic mass 54 94 has a density of 7 42g cm Calculate the volume occupied and the radius of the atom of this metal assuming it to be a sphere

CH3 g CH4 g H g CO g CH3 The reaction is carried out in a constant volume container at 500 C and has a half life of 14 5 min The reaction follows first order kinetics only dimethyl ether is present initially at a pressure of 0 40 atm Assuming ideal gas behaviour mark out the total pressure of the system after 12 min a 0 523 atm b 0 749 atm d 1 atm 1 66 c 0 861 atm

12 The oxide which cannot act as a reducing agent is a CO c NO b ClO d SO 1995 13 Which substance is serving as a reducing agent in the following reaction 14H Cr 0 3Ni 7H O 3Ni a H b CrO d Ni c H O 1994 14 The oxidation state of I in H4106 is b 1 d 5 15 a 1 c 7 1994 On electrolysis of dilute sulphuric acid using platinum electrodes the product obtained at the anode will be a hydrogen b oxygen c hydrogen sulphide d sulphur dioxide 1992

22 The molarity of a solution obtained by mixing 750 mL of 0 5 M HCl with 250 mL of 2 M HCl will be a 1 00 M c 0 975 M JEE Mains 2013 b 1 75 M d 0 875 M

A compound was found to contain 14 34 oxygen The minimum molecular weight of the compound is 1 111 5 g 2 223 15 g 3 97 62 g A 495 26 a

The rate of a first order reaction is 0 04 mol s at 10 seconds and 0 03 mol 1 s 1 at 20 second after initiation of the reaction The half life period the reaction is NEET 201 1 54 1 s 3 341 s 2 24 1 s A A 1 s

CsBr crystallises in a body centred cubic lattice The unit cell length is 436 6 pm Given that the atomic mass of Cs 133 and that of Br 80 amu and Avogadro number being 6 023 x 1023 mol 1 the density of CsBr is 1 42 5 g cm 3 8 25 g cm 3 2 0 425 g cm 4 4 25 g cm

A zinc electrode is placed in a 0 1M solution at 25 C Assuming that the salt is 20 dissociated at this dilutions calculate the electrode reduction potential E Zn Zn 0 76V EQUILIBRIUM CONSTANT

Problem 9 3 Can phosphorus with outer electroni configuration 3s 3p form PH

EMF of the following cell is 0 634 volt at 298 K Pt H 1 atm H aq KCI IN Hg Cl s Hg Calculate pH of the anode compartment Given E CI Hg Cl Hg 0 28 and 2 303 RT F 0 059

When sulphur is heated at 800 K the initial pressure of 1 atm decreases by 20 at equilibrium K of the reaction S g 4S g ono A 4 2 is 1 0 2 2 0 512 3 1 51

olution t K 7 t 2 303 AO log k A Example 10 A first order reaction has a specific rate constant of 2 x 10 s How much time it will take for 20 gm to reduce to 5 g 20 310 15 t 2 303 k log 2 303 2 303 20 k 5 A A log log4 10 3 0 693 25 d 1 693 1 s 2303 log le AO of 2305 107 20 4 F 2303 2x10 34

1 a A mixture of hydrogen and oxygen at one bar pressure contains 20 by weight of hydrogen Calculate the partial pressure of hydrogen b A sample of gaseous arsine AsH3 in a 500 mL flask at 300 torr and 223 K is heated to 473 K at which AsH3 decomposes to solid arsenic and H gas The flask is then cooled to 273 K at which the pressure in flask is 508 torr Calculate the of ASH decomposed

Write the balanced chemical equation for the following and identify the type of reaction in each case Potassium iodide aq Barium bromide s a Potassium bromide aq Barium iodide aq b Zinc carbonate s Zinc oxide s Carbon dioxide g c Hydrogen g Chlorine g Hydrogen chloride g d Magnesium s Hydrochloric acid aq Magnesium chloride aq Hydrogen

5 A 0 66 kg ball is moving with a speed of 100 m s The associated wavelength will be h 6 6 x 10 4 Js 34 1 6 6 10 34 X m 3 1 0 x 10 32 m 2 1 0 10 35 m 4 6 6 x 10 32 m

5 What mass of C 4 with t1 2 equal to one curie 5730 year has activit Roorkee 1986

0 A metal surface of threshold frequency 5 3 10 4 sec 1 is exposed to a photon of radiation having energy 3 5x10 19 J Will it exhibit photoelectric effect

Iron exhibits bcc structure at room temp Above 900 C it transforms to fcc structure The ratio of density of iron at room temperature to that at 900 C assuming molar mass and atomic radij of iron remains constant with temperature is 3 2 1 2 4 3 3 2 3 291625 3 3 4 2 4 13 2

5 A student forgot to add the reaction mixture to the round bottomed open flask at 27 C and put it on the flame After a lapse of time he realized his mistake using a pyrometer he found the temperature of the flask was 477 C What fraction of air would have been expelled out

11 2 g carbon reacts completely with 19 63 litre of 0 2 at NTP The cooled gases are passed through 2 litre of 2 5N NaOH solution Calculate concentration of remaining NaOH and Na CO3 in solution CO does not react with NaOH under these conditions

1 A non volatile solute A tetramerises in water to the extent of 80 2 5 g of A in 100 g of water lowers the freezing point by 0 3 C The molar mass of A in mol L is K for water 1 86 K kg mol a 62 c 155 b 221 d 354 2019

If 0 5 mole H is reacted with 0 5 mole I in a ten litre container at 444 C and at same temperature value of equilibrium constant K is 49 the ratio of HI and will be 1 1 7 4 49 2 3 1 7

9 In hydrogen atom energy of first excited state is 3 4 eV Then find out K E of same orbit of hydrogen atom a 3 4 eV c 13 6 eV b 6 8 eV d 13 6 eV 2002

1 For a first order reaction rate constant is x 10 5 s having E 1800 kJ mol Then value a of InA at T 600K is 1 151 7 3 24 7 2 349 3 4 11 34

Assertion In rock salt structure the sodium ions occupy octahedral voids Reason The radius ratio r r in case of NaCl lies betwen 0 225 to 0 414 1 A 4 D 2 B 3 C Ans 3

Based on the hints given find out the atomic number and write down the subshell electronic configuration of elements Symbols used are not real i A period 3 group 17 ii B period 4 group 6 When the last electron of an atom was filled in the 3d subshell the subshell electronic configuration was 3d Answer the questions related to this atom Complete subshell electronic configuration Atomic number Block umber

mctive Find the current supplied in amp for electrolysis of 300 ml aqueous NaCl solution If after 5 minuters pH of final solution was found to be 12 with current efficiency 96 5

Due to difference in degree of adsorption of gases by charcoal a mixture of noble gases can be separated by adsorption on a burnt charcoal sbroll b coconut charcoal c powdered charcoal d coke

Phenolphthalein does not act as an indicator for the titration between B NaOH and CH3COOH D Ba OH 2 and HCI A KOH and H SO4 C Oxalic acid and KMnO4

The dipole moment of The dipole moment of B 1 D 1 5 D Correct Answer C 2 25 D Your Answer X is 1 5 D is

A radioactive sample has initial activity of 28 dpm 30 minutes After 69 3 minutes it was found to have an activity of 28 dpm Find the number of atoms in a sample having an activity of 100 dpm Divide your answer with 100

4 Which mode of expressing concentration is independent of temperature a Molarity c Formality mn1 b Molality d Normality

27 790 28 53 The substance having highest conductivity at room temperature among the following is a 0 1 N HC1 c graphite PO b d 0 1 N NaCl 2015 TAST glass TISTIUS mivo offs ai re

3 Calculate the binding energy per nucleon of Li isotope which has the isotopic mass of 7 016 amu The individual masses of neutron and proton are 1 008665 amu and 1 007277 amu respectively and the mass of electron 0 000548 amu

7 20 mL of CH3COOH reacts with 20 1 mL of C H5OH and produce CH3COOC H5 according to the following reaction density of CH3COOC H5 is 0 902g mL CH3COOH C H5OH CH3COOC H5 H O a Which one is the limiting reagent in this reaction b If 27 5 mL of pure CH3COOC H5 is produced then find the percentage amount of production density of CH3COOH and C H5OH are 1 05g mL and 0 789g mL respectively

17 An element crystallises in fcc lattice having edge length 400 pm What is the maximum diam atom which can be placed in interstitial site without distorting the structure 4 140 pm 1 117 pm 2 130 pm 3 135 pm