Physical Chemistry Questions

14 The dissociation of nitrogen pentaoxide is a first order reaction In first 12 min 75 of nitrogen pentaoxide is dissociated What amount of nitrogen pentaoxide will be left behind after one hour of the start of reaction 1 3 01 2 0 21 3 0 098 4 None of these

Which of the following statements is incorrect in the context of the B F bond in BF3 A B The bond energy of B F bond is very high than for any other single BF bond Correct Answer The unusal shortness and strength of BF bond may be explained by p d interation between boron and fluorine atoms C The unusal shortness and strength of BF bond may be explained by p p interaction hotwoon horon and fluoring

false for following itement CaCO aragonite For the reaction CaCO3 Calcite given A G298 Calcite 1128 8 then Calcite form is more stable at standard conditions For the reaction kJ mol A G298 aragonite 1127 75 kJ mol C diamond 2H g CH g AH C g 4H g CH g AH a b then more heat is evolved in reaction b AH L g AH 1 s at 25 C For the exothermic reaction 2Ag s 1 2O g FTTT B TTFT C TFTT 2Ag O s at 298 K AH AU D TTTT

Pbl4 does not exist because Question Type Single Correct Type 1 lodine is not reactive 2 Pb IV is oxidizing and I is reducing agent 3 Pb IV is less stable than Pb II 4 Ph 4 is not easily formed

For a reaction activation energy is zero What is the value of rate constant at 300 K if K 1 x 10 6s at 280K R 8 314 JK 1 mol Question Type Single Correct Type 1 2x 10 6 1 2 4x10 6 S 1 3 1 106 S 1

8 The rate law of a reaction A B Product is rate k A B On doubling the concentration of A and halving the concentration of B the ratio of new rate to the earlier rate of reaction will be 1 n m 1 3 2m n 2 2n m 4 m n

Which of the following is correct for nature of graph as per Moseley s X ray experiment A vs atomic mass is linear B vvs atomic mass is linear C v vs vapour density is linear D vs atomic number is linear where v frequency of X rays emitted

3 KMnO4 can be prepared from K MnO4 as per the reaction 3 MnO 2H O2 MnO MnO2 4OH The reaction can go to completion by removing OH ions by adding 1 KOH 2 CO 3 SO 4 HCI

Two flasks A and B have equal volumes The molecules in flask A are moving two times faster than the molecules in flask B The number of molecules in flask A is eight times the number of molecules in flask B Which of the following is true about the number of collisions with the walls a The number of collisions with the walls in flask A is four times that in flask B b The number of collisions with the walls in flask B is four times that in flask A c The number of collisions with the walls in flask A is 16 times that in flask B d The number of collisions with the walls in flask B is 16

Density of H g at 27 C at 0 25 gm lit If Vander waal s gas constant b for H is 0 5 lit mol the for H g A Compressibility factor Z 1 067 B Molar volume V 4 litre mole C Compressibility factor Z 1 26 D Molar volume V 8 litre mole

A balloon filled with a gas absorbs 1kJ of heat expands against a constant pressure of 1 atmosphere from a volume of 20 litres to 23 litres The value of AE would be approximately Question Type Single Correct Type 1 600 J 2 1200 J 3 696 J

46 SCQ en C The BC13 is a planar molecule whereas NC13 is pyramidal because A N Cl bond is more covalent than B Cl bond B C D B Cl bond is more polar than N Cl bond Nitrogen atom is smaller than boron Correct Answer BC13 has no lone pair but NC13 has a lone pair of electrons

A Solution is prepared in a cold room 4 degree c by dissolving 175 7 g of potassium nitrate in exactly 750 ml of water The resulting solution had a volume of 745 ml 1 Calculate the molarity of the resulting solution

Which one of the following statements related to lanthanons is incorrect 1 Europium shows 2 oxidation state 2 The basicity decreases as the ionic radius decreases from pr to Lu 3 all the lanthanons are much more reactive than aluminium 4 Ce 4 solution are widely used as oxidizing agent in volumetric analysis

2 Which one of the following is wrongly matched 1 Saponification of CH3COOCH Second order reaction 2 Hydrolysis of CH3COOCH3 Pseudo unimolecular reaction 3 Decomposition of H O First order reaction 4 Combination of H and B to give HBr Zero order reaction

The de Broglie wavelength 2 associated with a photoelectron varies with the frequency v of the incident radiation as vo is threshold frequency JEE Main 2019 1 v vo 1 x 3 x 1 v v 2 1 2 x 4 x 1 1 v vo 4 1 v v 3

Calculate the enthalpy of formation of cane sugar C12H22011 5650 kJmor 390 kJmol 1 290 kJmol Given AcHGHz2011 ACH C ACHH 300 kJ mol 1 O 670 kJ mol 1 O 1280 kJ mol 1 O 2220 kJ mol 1

A molecular adduct is formed between BF and Et O Which of the following values desc coordination number CN valency V and oxidation state OS of B atom in this adduc A CN 4 V 4 and OS 3 B CN4 V 3 and OS 4 C CN 4 V 3 and OS 3 D CN 3 V 3 and OS 4

49 SCQ In borax the number of B 0 B and B OH bonds are respectively A five and four B four and five C three and four D en five and five Correct Answer

Q No 70 For the decomposition 2N205 g 4NO2 g O g activation energy Ea N205 g 2NO2 g O2 g activation energy Ea then of N O5 g it is given that Ea 2Ea Ea Ea Ea Ed

In a vessel O gas molecules were adsorbed on solid surface causing its partial pressure to decrea from 1 atm to 0 5 atm Given NA 6 1023 volume of the vessel 2 24L T 273K total area of solid surface 10 cm Number of active sites per unit area 10 4 m Find the number of O2 molecules adsorbed per active site

1 In the formation of sulphur trioxide by the contact process 2SO 0 2SO3 the rate of reaction was measured as 3 0 104 mol Ls d 0 dt The rate of reaction expressed in terms of SO3 will be 1 3 0 104 mol Ls 2 6 0 x 104 mol L s 3 1 5 104 mol L s 4 4 5 x 104 mol I 1 S C

The graph between y2 and r radial distance is shown below This represents JEE Main 2019 lyf 1 1s orbital 3 2p orbital 2 2s orbital 4 3s orbital

Select order of dissociation constant in aqueous solution at 298 K A B C D Wen H O H S H Se H Te Correct Answer H Te H Se H S H O H Te H Se H O H S H Te H S Hose HO

Q 29 4 1 00 26 On addition of 1mL solution of 10 NaCl to 10mL gold solution in the presence of 0 025 g of starch the coagulation is prevented because starch has the following gold numbers O 25

7 The pH of a 0 01 M solution of a monobasic acid is four Which one of the following statements about the acid is incorrect 1 When a little NaOH is added it will form a buffer solution 2 It is a weak acid 3 Its sodium salt will be acidic 4 Its sodium salt will be basic

3 Four species are listed below i HCO3 iii HSO4 ii H30 iv HSO3F Which one of the following is the correct sequence of the acid strength 1 iv ii iii i 3 i iii ii iv 2 ii iii i iv 4 iii i iv ii

Which of the following reactions is not correct according to the law of conservation of mass A 2Mg s O g 2MgO s C3Hg s O g CO g H O g B C D 4 s 50 g P4010 s CH4 g 20 g CO g 2H O g

Which of the following order is correct A B Correct Answer Clo CIO CIO C1 0 bond order 3 CO32 CO CO2 C O bond strength 3 C PO4 SO4 Number of coordinate bonds 2

Q 36 4 1 00 19 For a first order reaction A products the concentration of A changes from 0 1 M to 0 025 M in 40 minutes The rate of reaction when the concentration of A is 0 01 M is O 3 47 10 M min 0 5

Q 7 moderate O 4 1 Which of the following is true in respect of adsorption AG 0 AS 0 AH 0 O AG 0 AS 0 AH 0 O AG 0 AS 0 AH 0 00 19 O AG 0 AS 0 AH 0

Q 30 TE 4 1 00 26 For the reaction N 0 2NO 0 K N d NO dt Given d 0 dt 2 K N O and d0 K3 N O5 dt The relation in between K K and K is

What contribution did John Dalton make to atomic theory A B C D he discovered that every atom was positively charged he discovered that every every element consisted of one type of atom he discovered that atom had nuclei he discovered that atoms could be divided into smaller parts

11 The pH of a buffer is 6 745 When 0 01 mole of NaOH added to 1 litre of it the pH changes to 6 832 Its buff capacity is 1 0 187 3 0 076 2 0 115 4 0 896

Potassium sorbate C6H7KO is an additive used to prevent molding of cheese Its conjugate acid monoprotic has Ka 1 74x10 5 Find the pH of an aqueous solution containing 2 55 g of potassium sorbate in 500 0 mL Select one O a 10 65 O b 8 65 O c 3 11 O d 4 76 O e 2 55

1 A solution containing 10 2 g glycerine per isotonic with a 2 solution of glucose What is the molecular mass of glycerine a 91 8 g b 1198 g c 83 9 g d 890 3 g nls exerted

35 A container of volume 2 24 L can withstand a maximum pressure of 2 atm at 298 K before exploding The maximum amount of nitrogen in g that can be safely put in this container at this temperature is closest to 26 a 2 8 c 1 4 b 5 6 d 4 2 und shown holow

An element with mass number 95 have 4 unit positive charge and 25 more neutrons than electrons in the given ionic state Its atomic number is Z then find the value of Z 10

Q 11 4 1 00 19 Bauxite ore is concentrated by O Froth floatation Electromagnetic separation O Chemical separation

Which one of the following statements is true for all the alkali metals A B Their nitrates decompose on heating to give NO and 02 D Their carbonates decompose on heating to give CO and the metal oxide C They react with oxygen to give mainly the oxides M 0 Correct Answer They react with halogens to give halides MX

29 Given below are few reactions with some expressions Mark the expression which is not correctly matched a For concentration cell Ag Ag C Ag C Ag 0 0591 C Ecell 1 C2 b For the cell 2Ag H 1 atm 2Ag 2H 1 M 0 0591 Ecell Ecell 2 12 Ag 1 H 1 c For an electrochemical reaction at equilibrium aA bB 0 0591 log Excell ne n d For the cell M 0 0591 E E log CC dD C D d A B n aq log ne M s 1 log

The depression in freezing point of 0 01m aqueous CH3COOH solution is 0 02046 1m urea solution freezes at 1 86 C Assuming molality equal to molarity pH of CH3COOH solution is 1 2 3 3 2 2 3 4 4 2

Q 35 4 For a reaction xg yg z g the half life period is 10 min in what period of time would the concentration of X be reduce to 10 of original concentration 20 min O 33 min mi 1 00 24

03 Be and a proton are accelerated by the same potential their de Broglie wavelengths have the ratio assume mass of proton mass of neutron 1 1 2 2 1 4 3 1 1 4 1 3 3

Q 35 O Silver C 4 In electro refining of metal the impure metal is made the anode and a strip of pure metal the cathode during the electrolysis of an aqueous solution of a complex metal salt This method cannot be used for refining of Copper 1 00 03 O

3 13 When 10 ml of 0 1 M acetic acid pK 5 0 is titrated against 10 ml of 0 1 M ammonia solution pK 5 0 the equivalence point occurs at pH 1 5 0 3 7 0 2 6 0 4 9 0

If the amount of 9 0 x 10 3 M Pb2 ions is present in each of the following buffer solutions which of the buffer solutions given below will form Pb OH 2 precipitate Ksp Pb OH 2 1 2 x 10 15 one or more than one answers a buffer with pH 9 00 b buffer with pH 8 00 c buffer with pH 7 00 a only b only c only a and b b and c a and c W a b and c None of the three buffers form precipitate after Pb2 ions are added

6 Determine the H O partial pressure at 1000 K when 10 mole of H gas is exposed to the air AG using standard free energy change for the reaction H2 g 1 2O2 g H2O g which is AGO 246 55 T 103 in kJ mole

Sodium bicarbonate is reacted with concentrated hydrochloric acid at 37 C and 1 00 atm The reaction of 6 00 kg of sodium bicarbonate with excess L of CO2 hydrochloric acid under these conditions will produce Select one O a 1 82 x 104 O b 1 09 x 10 O c 8 70 x 10 O d 2 85 x 104 O e 1 82 x 10

1 In the Hall process aluminium is produced by the electrolysis of molten Al O3 by the following reactions How many second would it take to produce enough aluminum by the Hall process to make a case of 24 cans of aluminium soft drink if each can uses 5 0 g of Al a current of 9650 amp is employed and the current efficiency of the cell is 90 0 1 203 2 2 148 14 3 333 4 6 17 2 Contact Number 9667591930 8527521718 0 066 1 1 230 V 2 0 858 V 3 0 80 V 4 0 8274 V 5 A fuel cell develops an electrical potential from the combustion of butane at 1 bar and 298 K C4H10 g 6 502 g 4 CO2 g 5H O 1 What is E of a cell 1 4 74 V 2 0 547 V 3 4 37 V 4 1 09 V The electrolysis of acetate solution produces ethane according to reaction 2 CH3COOC H6 g 2 CO g 2e 6 The current efficiency of the process is 80 What volume of gases would be produced at 27 C and 740 torr if the current of 0 5 amp is passed through the solution for 96 45 min 1 6 0 L 2 0 60 L 3 1 365 L 4 0 91 L 2 303 RT F For cell reaction 2H g O g 2H O 1 A S298 0 32 kJ K What is the value of AH 8 H O 1 298 Given O2 g 4H aq 4e2H O 1 E 1 23 V 1 285 07 kJ mol 2 570 14 kJ mol 3 285 07 kJ mol 4 None of these 3 100 mL of 0 05 M CuSO4 aq solution was electrolyzed using inert electrodes by passing current till the pH of the resulting solution was 2 The solution after electrolysis was neutralized and then treated with excess KI and 7 formed 1 titrated with 0 04 M Na2S O3 The standard reduction potential of normal calomel electrode and reduction potential of saturated calomel electrodes are 0 27 and 0 33 volt respectively What is the concentration of CI in saturated solution of KCI Calculate the required volume in mL of Na S O3 1 112 5 mL 2 100 mL 3 125 mL 4 None of these 4 reaction 8 If the equilibrium constant for the H aq OH aq H O 1 is 10 3 at certain temperature then what is the E for the reaction 2H O 1 2e H g 2OH aq Given 1 0 1 M 2 0 01 M 3 0 001 M 4 None Copper reduces NO into NO and NO depending upon concentration of HNO3 in solution Assuming Cu 0 1 M and PNo PNO 10 bar At which concentration of HNO3 thermodynamic tendency