Physical Chemistry Questions

Calculate the potential developed by a voltaic cell using the following reaction if all dissolved species are 0 085 M 2 Fe You may need to use the following data aq H O aq 2 H aq 2 Fe aq 2 H H O aq 2 H aq 2 e 2 Fe aq e Fe aq Potential V 2 H O l E 1 77 V E 0 771 V

The mole fraction of ethanol in water is 0 08 Its molality is A 6 32 mol kg B 4 83 mol kg SR 0 08 2 B 4 83 mol kg A 6 32 mol kg C 3 82 mol kg 493 faft 2 C 3 82 mol kg D 2 84 mol kg D 2 84 mol kg

e Hall coefficient of a semiconductor is 3 22 X 10 power 4 m3 C Its resistivity is 9 X 10 power 3 mm The mobility of charge carriers will be OPTIONS 0 0035 X 10 power 2 m2 Vs 035 X 10 power 2 m2 Vs 0 35 x 10 power 2 m2 Vs

16 Given the following reactions 1 CH O CH O H 2 CH O N 3H 3 N 3H 2NH the AH for N H H 2NH is A 18 0 B 75 0 N H CHO C 148 AH 65 0 kJ AH 37 0 kJ AH 46 0 kJ kJ D 192 E 18 0

10 1 00 g of a non electrolyte solute dissolved in 50g of benzene lowered the freezng point of benzene by 0 40K The freezing point depression constant of benzene is 5 12K kg mol Find the molar mass of the solute

Statement 1 Every 100 ml of oxygenated blood can deliver 5 ml of O to the tissue under normal physiological conditions Statement II Every 100 ml of deoxygenated blood deliver approximately 4 ml of CO to alveoli A Statement I is correct and Statement II is wrong B Statement I is wrong and Statement II is

d In a study of the water gas shift reaction CO2 g H2 g CO g H O g a mixture of CO2 and H2 initially containing 42 4 mol H2 was brought to equilibrium in a closed vessel at 1259 K The system was then found to contain 15 2 mol H Calculate Kp and AG for the reaction at 1259 K 3

f the activation energy of a reaction varies as E aRT bRT2 a 0 b 0 hen what will be the slope of In N versus T where N is the fraction of mol ecules having energy greater than activation energy A b B b C b a D b a

CH CO H An analytical chemist has determined by measurements that there are 8 483 moles of carbon in a sample of acetic acid How many moles of hydrogen are i sample Round your answer to 4 significant digits 0 9

WBSU Year 2017 5 d 20 85 g of PC15 is taken in a 4 L closed vessel at 250 C The equilibrium pressure of the mixture is found to be 1 825 atm Find out the partial pressure of Cl and the value of Kp 3

The energy profile diagram for an exothermic reaction is shown below energy reactants AE products The change in energy AE in the diagram represents the Select one O energy absorbed when bonds in the reactants break O energy difference between the reactants and the transition state O activation energy of the forward reaction

IUPAC name of chloroform is O Chloromethane O Dichloromethane O Trichloromethane

You are asked to dissolve 38 45 g of Na2HPO4 in 450 0 mL of distilled water Please determine the answers to the following four concepts and select the most appropriate answer for each concept from the list below 4 answers should be selected a m v b Concentration in mol L c Reaction capacity d Normality N

APA 1 66V and K of Al OH 3 1 10 33 The reduction potential of sp e above couple i e EOH IAI OH AI at pH 14 is approximately equal to X 0 3 V Find out the value of X to nearest integer

The absorption cross section on the ordinate of the ozone absorption spectrum is defined by Transmittance T e b where n is the number of absorbing molecules per cubic centimeter is the absorption cross section in square centimeters cm and b is the panthlength in centimeters cm The total ozone in the atmosphere is approximately 8 x 10 8 molecules above each square centimeter of Earth s surface from the surface up to the top of the atmosphere If this were compressed into a pathlength of a 1 cm thick layer the concentration would be 8 x 10 8 molecules cm Ultraviolet radiation in the 200 to 280 nm range is essentially completely blocked by ozone in the atmosphere but barely absorbed in the 315 to 400 nm range Using the ozone spectrum estima the transmittance T and absorbance A of this 1 cm sample at 280 and at 340 nm Question 11 of 15 T at 280 nm A at 280 nm T740 Absorption cross section 10 19 cm 100 0 60 0 60 0 x 1000 250 CIO H CO 300 Wavelength nm Harris Lucy Quantitative Chemical Analysis 10e 2020 W H Freeman and Company 350 Spectra of trace gases in the atmosphere At ozone s maximum absorption at a wavelength near 260 nm a layer of ozone is more opaque than a layer of gold of the same mass Data from U Platt and J Stutz Differential Absorption Spectroscopy Berlin Heidelberg Springer Verlag 2008

Chem Section B This section contains NUMERICAL VALUE TYPE questions Enter the correct numerical value in Read More A sample of hydrazine N H4 was dissolved in 0 1 L of water 5 ml portion of this solution was reacted with excess of FeCl3 solution and covered to complete the reaction Ferrous ions formed were estimated and it M requires 10 ml of KMnO4 solution 50 Given 4Fe N H4 N 4Fe2 4H KMnO4 5Fe 8H Mn 5Fe 4H O The amount of hydrazine in g present in 1 liter of solution is x Then the value of x is

The standard additions method was used to determine nitrite in a soil sample A 1 00 mL portion of the sample was mixed with 24 00 mL of a colorimetric reagent and the nitrite was converted to a colored product that produced an absorbance of 0 300 To 50 mL of the original sample 1 00 mL of a standard 1 00 x 10 3 M nitrite solution was added The same color formation procedure was carried out and the absorbance obtained was 0 530 What was the nitrite concentration in the original undiluted sample

WBSU Year 2011 3 c Determine the effect of introducing an inert gas keeping pressure of the system constant on the position of equilibrium of the following reaction N2 g 3H g 2NH3 g 3

AC Oce o 25801234 transienl interactions D CELL N cell D cell ACp Doe Noot 9540 1200 J mol K Using the above figure can you calculate the equlibrium constant between extracellula racellular folded protein N Denatured protein is designated D in the figure You ma inciples to calculate the value

A gaseous mixture contains 5 6 g of carbon II oxide and rest carbon IV oxide when it is enclosed in a vessel of 10 dm at 298 K it recorded a pressure of 2 0 bar What is the partial pressure of each oxide of carbon

Statement I In Finkelstein reaction the solvent used is dry acetone Statement II Dry acetone precipitates the NaCl or NaBr formed in the reaction and thus the reaction proceeds in the forward direction In the light of the above statements choose the correct answer from the options given below Statement I is false but Statement II is true Both statements I and II are true Both statements I and II are false Statement is true but statement II is

69 The degree of dissociation of 1 molecule of 1000 C and under atmospheric pressure is 40 volume If the dissociation is reduced to 20 at the same temp total equilibrium pressure c the gas is a 1 57 atm b 2 57 atm c 3 57 atm d 4 57 atm

21 Which of the following equations represents a AH f equation a CO2 g H2 g HCOOH HCOOH b CO g H O 1 C 2 C s 2 H2 g 2O2 g 2 HCOOH d C s H O 1 2O2 g HCOOH 1 C s H2 g O2 g HCOOH 1 e

3 Which of the following statements is false about gases At high temperature and low pressure the ideal gas behavior is followed At high pressure the volume of the real gas is less than the ideal gas volume At low temperature and moderate pressure the attractive forces between particles are dominant At high pressure the molecular distance between gas particles approaches molecular diameter so repulsive forces are dominar

31 Identify the correct statement for change of Gibbs energy for a system AG system at constant temperature and pressure AIPMT Prelims 2006 0 the process is spontaneous 0 the system has attaine 1 If AG system 2 If AG system equilibrium 3 If AG 0 the system is still moving system a particular direction 0 the process is no 4 If AG system

e Does the equilibrium constant of a chemical reaction depend on the following i Standard states chosen for the reactants and products ii The stoichiometric representation of the reaction Justify your answer 2 2

How many moles of ATP is obtained from the catabolism of 5g of a triglyceride made of a C16 fatty acid a C17 fatty acid and a C24 fatty acid Use the following molecular mass values for your calculations H 1g mol C 12g mol O 16g mol If you can also provide an explanation as to how to calculate how much water in Litres is produced that would be great

It is generally accepted that a solution has useful buffer capacity pH change resisting power provided that the value of salt or conjugate base acid for acidic buffer lies within the range of 1 10 to 10 1 Buffer capacity is maximum when Conjugate base acid Calculate the pH of a solution made by adding 0 01 mole of HCl in 100 mL of a solution which is 0 2 M in NH3 and 0 3 M in NH4Cl pK NH3 4 74 log2 0 3

5 You have 15mL of a 0 3M solution of His Lys Leu Asp adjusted to pH 9 You titrate your solution with 10mL of 0 2M HCI Relevant pKa values are 2 1 3 8 6 0 9 8 and 10 5 a Draw the structure of the tetrapeptide that predominates in solution before you add any HCI 5 marks

2 A B solid 2A g 3B g For the above hypothetical reversible balanced reaction at a particular temperature the value 3456 atm 5 Let the total pressure at equilibrium be x times as that of partial pressure of A Then find the value of 2x is

A effervescent tablet containing sodium bicarbonate and oxalic acid releases 0 25 mL of CO2 at T 298 15 K and p 1 atm If molar volume of CO2 is 25 0 L under such condition what is the percentage of sodium bicarbonate in each tablet Molar mass of NaHCO3 84 g mol O O O O 8 4 0 84 16 8 33 6

The vapour pressure of water at 80 C saturated with water the total pressure being 760 mm of Hg The contents of the vessel were pumped into 0 3 L vessel at the same temperature What is the partial pressure of O D 455 Hg C 123 5 Hg A 1350 Hg B 2263 3 Hg

Consider a hypothetical cell X s Yaq Xaq Y s AH 289 5 kJ The standard emf of the cell is 1 2 V If the efficiency of the cell is n the value of is neglect the change in entropy

Question 3 Let 21 and 22 be the complex roots of ax 2 bx c 0 where a b c 0 Then A 21 22 1 B 121 22 2 1211 1221 1 None of these Question 8 Let 21 and 22 be two roots of the equation 2 az b 0 z being complex Further assume that the origin 21 and 21 form an equilateral triangle Then a b a 2b 1 Point a 3b 1 Poin

2 The question concerns the buffering effect of acid base system i What is the pH of a solution of that contains 0 15 M Na H PO4 and 0 65 M Na 2HPO4 ii iii What would the concentration of Na H PO4 be at pH 6 if 0 15M Na 2HPO4 was adjusted to that pH What would be the concentration of Na H PO4 be at pH 3 if the solution in ii was adjusted to that pH Please provide the rationale behind this calculation

Isobutyl bromide on reaction with alc KOH followed by reaction with HBr gives Br Br x Br Br

Calculate the heat of formation of napthalene from the following data CO g L C S O g ii H g 1 2 O g iii C pHg S 120 g H O 1 10CO g GH O 1 H 94 405 Kcal H 68 3 Kcal H 94 405 Kcal

Select incorrect statement s A Entropy of an isolated system always remains constant during phase transition proces B AS 0 for reversible condensation of vapour surrounding C 4 G 0 for Br g at high temperature 2AB g 200 kJ D A g B g information AH AR a is 100 kJ mole

In the organic compound 5 CH CH CH C CH C CH the state of hybridization of carbons 2 4 and 6 are in the following sequence O sp sp sp O sp sp sp O sp sp sp O sp sp sp

A s A g If graph between the InP and P Partial pressure of A InP 1 40000 100 the temperature at which reaction is spontaneous 1 230 K 2 300 K By the equation In P represented as

In which of the following arrangements the order is INCORRECT according to the property indicated against it O O O Li Na K Rb Increasing metallic radius I Br F CI Increasing electron gain enthalpy with negative sign B C N 0 AP Mg Na F

Nitrogen and oxygen react to form nitric oxide NO All substances are in the gas phase If 0 473 atm of nitrogen and 0 416 atm of oxygen react what is the partial pressure of nitric oxide in mmHg when this reaction goes 64 complete The temperature and volume are constant

Let 21 and 22 be the complex roots of ax 2 bx c 0 where a b c 0 Then A 21 22 1 8 121 22 2 1211 1221 1 None of these Question Let z1 and 22 be two roots of the equation 2 az b 0 z being complex Further assume that the origin z1 and z1 form an equilateral triangle hen A a b B a 2b 1 Point al 3b

Mathematically the uncertainty principle is presented as Axx Ap 27 12 The value of m for d2 orbital is non zero Two electrons occupying the same orbital of an atom are distinguished by spin quantum number Electrons in the 3d orbitals have different spatial distribution consequently their shielding of one another is relatively small

Using the bond enthalpies in the bond energy values in KJ below calculate the Horxn For the combustion reaction of 2 moles of the following molecule C H O4 C H 413 C O 358 O H 463 C C 348 C O 799 O 495 diagram 4 OH a 3345 O b 4157 O c 5726 O d 2456 Oe 2678 CO OH

K water 1 86 K kg mol The temperature at which ice begins to separate from a mixture of 10 mass ethylene glycol is A 1 86 C B 3 72 C D 3 C 40410 R 5 fe 59 6 34 23 20 K 1 86 K kg mol A 1 86 C B 3 72 C 3 3 C D 3 C

Which of the following statement s is are correct Pot Tetracyanocuperate I tetrahedral complex Sod Tetracyanonickelate II is a square planar complex Pot Tetrachloridopatinate II is a tetrahedral complex Tetraamminecopper II sulphate is a squa

Question 2 Let build Frost diagram of P pH 0 and pH 14 at pH 12 Let find the value of pH that P change from unstable to stable state pH 0 H3PO4 0 933 H4P2O6 0 380 H3PO3 0 499 H3PO2 0 365 pH 14 PO43 1 12 HPO32 1 57 H PO2 2 05 P 0 89 P 0 100 P H 0 006 PH3 PH3

Which of the following will give a tertiary alcohol as product if reacting with C H5MgBr followed by hydrolysis HCHO CH3CHO min sec OLIO

The following reaction is an example of 4NH3 g 50 g 4NO g 6H O g i displacement reaction iii redox reaction a i and iv c iii and iv ii combustion reaction iv neutralisation reaction b ii and iii d i and ii