Physical Chemistry Questions

63 Electrode potential data are given below S A 3 2 Fe aq eFe aq Fe E 0 77 V Alaq 3e Al s E 1 66 V Br2 aq 2e 2Br aq E 1 66 V Based on the above data which statement s incorrect 8 1 Fe2 is stronger reducing agent than Br 2 Fe2 is stronger oxidising agent than Al 3 Al is stronger reducing agent than Fe2 2 4 Bris stronger reducing agent than Al 2

Consider two strong electrolytes NaCl and KCI The molar conductance Am and concentration C for strong electrolytes can be related as A A B C What can be said about the values of A and B for KCI and NaCl Both have same value of A as well as B Both have same value of A but different value of B Both have different value of A but same value of B Both have different value of A as well as different value of B

143 The vapour pressure of water at room temperature is lowered by 5 by dissolving a solute in it then the approximate molality of solution is 1 2 3 4 2 1 4 3 1 x y

For the following solution determine whether it is equilibrium and justify your choice If it is not use Le Chatelier s principle to predict and justify the results Would a ppt be expected to form if a solution is prepared from a mixture of 1 0 L of lead II nitrate solution that was 0 00010M was added to 1 0L of 1 4 10 3M in potassium sulfate is added to a solution that is 5 0 10 5M sodium chromate Would you expect a precipitate to form If so Justify

Ozone is unstable with respect to decomposition to ordinary oxygen 203 g 302 8 K 1 3 x 1057 How many ozone molecules are present in the atmosphere at equilibrium in 17 86 million cubic meters of air at 24 6 C and 610 7 mmHg Record your answer with no decimals

In an analysis the complete combustion of 174 2 mg of compound A produces 490 6 mg of carbon dioxide and 201 1 mg of water vapour Compound A contains carbon hydrogen and oxygen Determine the empirical formula of compound A Use the molar masses from the textbook I have assigned for the course Empirical formula of compound A

11 A metal can of volume 2000 0 cm3 contains 2 0 g of nitrogen gas and 6 0 g of hydrogen gas at exactly 200 C What is the total pressure of gas in the can Ans 6 MPa 12 The product of the pressure and volume of a sample of hydrogen gas at 0 00 C is 80 0 I Ans a 0 0352 mol b 565 x 10721 c 138 42 11

1 A 25mL 0 05M HCL solution was mixed with 75 00mL 0 01M KOH solution 20mL of the resulting sol ution was titrated for neutralizatio n using a standard Ba OH 2 soluti on and its 25mL was required Th e polarity of Ba OH 2 solution is a 0 004M b 0 002M c 0 001M d 0 02M

Hydrocarbon contains 600 by mass carbon and its one molecule weighs 93 33 x 10 24 g Which of the following statement s is are correct NA 6 0 x 10 7 O Empirical formula is CH O Empirical formula is CH2 O Molecular formula of C3Hg O Molecular formula is C4H8

The electronic configuration of the element which is just above the element with atomic number 43 in the same periodic group is A Ar 3d 4s B Ar 3d 0 4s 4p5 C Ar 3d4s D Ar 3d 4s 4p E Ar 3d 4s

An acid base indicator has K 3 0x10 The acid form of the indicator is red and the basic form is blue Then which of the following statement s is are correct Take log3 0 48 pH is 4 04 when indicator is 75 red pH is 5 00 when indicator is 75 blue pH is 5 00 when indicator is 75 red pH is 4 05 when indicator is 75 blue

No 12 A solution containing a metal complex absorbs at 480 nm with molar extinction coefficient of 15 000 L mol cm If the path length of the cell is 1 0 cm and transmittance is 20 5 the concentration in mol L of the metal complex is 1 37 10 5 2 29 10 5 4 59 x 10 5 8 75 x 10 5 A B C D

9 An electrolytic cell is composed of Cu and Zn current of 9 65 A is drawn from a cell for 1 hou Then the loss in mass at anode and gain in mas at cathode respectively could be 1 11 77 g 11 43 g 3 22 86 g 23 54 g 2 11 77 g 10 g 4 23 54 a 2386

At 75 C the vapor pressures of HNO3 and H O are respectively 4670 Pa and 11500 Pa on a nitric acid solution whose mass fraction in HNO3 is 0 650 Knowing that P HNO3 71990 Pa and P H O 38540 Pa Calculate the partial pressure Pi of each component for the ideal solution total pressure for the ideal and the real solution and the mole fractions of each component in the vapor x vapor for the ideal and actual solution

75 Dimerisation of NO is an exothermic reaction If enthalpy of reaction is AH then the minimum value of activation energy for forward reaction E will be 1 Equal to AH 2 Equal to zero 3 Greater than AH 4 Greater than Threshold energy 2

0 In the hypothetical molecule AX L where A is central atom X is surrounding atom L is lone pair n is the number of lone pair for which possible value of n will the dipole moment of the molecule be minimum

A straight glass tube of length 450cm has two inlets X and Y Through inlet X the gas with vapour density 36 and through inlet Y an unknown gas are introduced at same time and same T and P The distance of point at which two gasses meet is 180cm from the end X what is the weight of 2 8lit of that gas in grams at STP

How long must a 50 0 A current be passed through an electrolytic cell fo refining copper to produce 3 00 mole of copper Options 1 O 1 50 hrs 2 O 1 61 hrs 3 O 2 50 hrs 4 O3 21 hrs

he reaction 2N O 4NO O initial pressure is 500 atm and rate constant k is 1 3 38 10 after 10 min the final pressure of N O is 490 at n 250 atm 480 atm 420 atm

A Figure 1 16 Potential energy and kinetic energy The potential energy initially motionless bicycle and rider at the top of the hill is converted to kinetic energy as the bicycle moves down the hill and loses potential energy All other forms of energy the energy stored in a stretched spring in a weight held above your head or in a chemical bond are classified as potential energy An object ha potential energy by virtue of its position relative to other objects Potential energy is in essence the stored energy that arises from the attractions and repulsions an object eriences in relation to other objects is converted into

5 Which of the following is not correct 1 Molar conductance of a solution increases with dilution 2 Equivalent conductance increases with dilution 3 Specific dilution conductance increases with 4 At infinite dilution each ion cation or anion plays a definite role towards electrical conductance

If x gram of oxalic acid can completely be oxidised by 400 ml of 0 1M acidified permanganate solution according to the following equation then value of x is MnO C 0 H Mn CO H O

55 10 g of each Pb Al Ag and Cu is given 100 kJ of heat and temperature rise is x y z and w kelvins respectively Then select the correct relation given heat capacity in J g k is 0 9 0 386 0 233 and 0 128 for Al Cu Ag and Pb respectively 1 x y 3 z w 2 y w 4 x z

The correct name of the compound Cu NH NO3 according to IUPAC system is O Tetraamminecopper II dinitrite Tetraamminecopper II nitrite O Cupraammonium nitrate

4 2l 2 9 The possible exchanges for a de configuration is 1 4 2 10 3 8 4 6

Hydrazine can be used in fuel cell N H4 aq O2 g N2 g 2H O 0 If AG for this reaction is 600 kJ what will be the E for the cell 1 1 25 V 3 1 57 V 2 1 50 V 4 1 75 V

7 Use the Maxwell distribution of speeds to estimate the fraction of N molecules at 400 K that have speeds in the range 290 to 300 m s Ans 1 023 10 8 In the following questions calculate the final volume of gas in Litre at the specified conditions assuming the temperature and mass remain constant Ans a 0 15 I b

Which of the following statements is are correct 1 There are 5 orbitals in the subshell 2 The d orbitals can accommodate 14 electrons 3 The first shell contain s and p orbitals 4 The s orbital can accommodate 2 electrons 1 and 4 O2 and 3 3 and 4

4 Consider the irreversible reaction for the conversion of chlorophenol C6H4OHCl or CP to dioxin C6H3C1O2 2 C6H4OHCl 2 02 aq C6H3CIO2 2 H O TCP k CP 2 O aq 5 a If k 10 L 5 mol 5 sec how long would be required to form 109 M dioxin in a batch reactor with an initial solution containing 107 M chlorophenol and a constant O aq of 2 5 x 104 M b Provide the structure for chlorophenol and dioxin explain their sources in the environment and comment on their relative toxicity

8 Following limiting molar conductivities are given x Scm mol 2 m H SO4 20 m K SO4 y Scm mol m CH COOK z Scm mol 2 in S cm mol for CH3COOH will be 1 x y 2z 2 x y z x y 3 X V Z 4

Which of the following is are not a buffer solution 500 mL of 0 1 N CH COOH 500 mL of 0 1 N NaOH 500 mL of 0 1N CH COOH 500 mL of 0 1 N HCI 500 mL of 0 1 N CH COOH 500 mL of 0 2N NaOH 500 mL of 0 2 N CH COOH 500 mL of 0 1N NaOH

Solubility product Ksp of CaCO3 at 25 C is 10 10 What would be the concentration of H CO3 is required to precipitate CaCO3 from solution of 10 3 M Ca 2 ions 10 7 10 9 10 6 10 13 Marks 4 1

Mechanism of reaction 203 302 can be given as K 03 O O fast K 0 020 slow Which of the following is correct rate law K r K 03 0 r K 0 1 0 r K K 03 0 r K3K1 0 1 03 K

Mechanism of reaction 203 g 302 g can be given as 0 0 0 fast 03 0 0 20 slow Which of the following is correct rate law Or K 03 0 r K 0 0 Or K K 03 0 r K K 0 03 K

Select the correct statement s A CsCl changes to NaCl structure on heating B NaCl changes to CsCl structure on applying pressure C Co ordination number decreases on applying pressure D Co ordination number increases on heating 1 A B 2 A B C 3 B C D 4 A B C D

13 3 The ions O F Na Mg2 and Al are isoelectronic Their ionic radii show a a decrease from O to F and then increase from Na to Al b a significant increase from O to Al c a significant decrease from O to Al d an increase from O2 to F and then decrease from Na to Al 3

12 The product of the pressure and volume of a sample of hydrogen gas at 0 00 C is 80 0 J Ans a 0 0352 mol b 5 65 x 102 c 138 42 J a How many moles of hydrogen are present b What is the average translational kinetic energy of the hydrogen molecules c What is the value of the product of pressure and volume at 200 C

Equivalent conductivity of BaCl2 H SO4 and HCl are x x2 and x cm eq at infinite dilution If conductivity of saturated BaSO solution x 5 cm then Ksp of BaSO4 is A B D 500x X X2 2X3 105x2 X X 2X3 2 5 x 105x X X2 X3 0 25x X X2 X3

D Classify following into carbohydrates protein fat vitamin Cereals ghee paneer wheat meat papaya milk egg bhakri cucumber orange fi oll carrot carbohydrates Protein Fat Vitamin

Which of the following statements is correct a Xion is larger in size than X atom b Xion is larger in size than X atom c X and Xions are equal in size d Xion is larger in size than X ion

of this mole 329 3 25 00 mL sample of a household cleaning solution was diluted to 250 0 mL in a volumetric flask A 50 00 mL aliquot of this solution required 41 27 mL of 0 1943 M HCI to reach a bromocresol green end point Calculate the mass volume percentage of NH3 in the sample Assume that the alkalinity results from the ammonia N 14 00 H 1 01 Cl 35 5 g mol LE

73 Which of the following pair of species illustrates law of multiple proportions 1 02 03 2 H O D O 3 CH4 C H 4 KOH KCI of Ma is 24 amu it means that an

View In English Gold number of hemoglobin is 0 03 Hence 100 mL of gold sol will require how much hemoglobin so that gold is not coagulated by 10 ml of 10 NaCl solution 1 2 3 Correct Answer 3 0 03 mg 30 mg 0 30mg 3 mg

Marks 0 In all other cases A collection of H atoms in 9th excited state returns to ground state Find the ratio of total number of spectral lines emitted without emitting any line in Brackett series to number of Brackett series lines

What would be percentage packing efficiency of the smaller cubes formed within a F C C arrangement by joining centres of the tetrahe voids Take 0225 0 0114 0 414 0 0710 0 732 0 392 1 414 2 83 3 1 05 O 12 22 48 02 58 07 23 58

Another application for dilutions A 24 hour urine for creatinine measurement frequently requires dilution In this example 1800 mL of urine is provided in 24 hours Before measurement the urine is diluted 1 5 and the result is 26 mg dL To calculate the final concentration based on total excretion in the 24 hour period use the following equation Total excretion total urine volume x concentration x dilution Total excretion 1800 ml 24 hr x 26 mg dL x 5 x dl 100 mL Total excretion 2340 mg 24hr or 2 34 g 24 hr 4 Calculate the 24 hour excretion of creatinine if the urine volume is 2 5 L The specimen was diluted 1 4 before measurement The measured creatinine concentration was 25 mg dL What is the total excretion in mg 24 hrs

3 Which of the following statements is not correct 1 Vacancy defect results in decrease in density of substance 2 Vacancy defect can develop when a substance is heated 3 Interstitial defect increases the density of the substance 4 Ionic solids show Schottky defects only

Compound A has the molecular formula C5Hg and is optically active Or catalytic hydrogenation A yields B Compound B has the molecular formula C5H10 is optically inactive and cannot be resolved into separat enantiomers Compound C has the molecular formula C6H 0 and it is optically active Compound C contain no triple bonds Catalytic hydrogenation of C yields D Compound D has the molecular formula C6H14 is optically inactive and cannot be resolved into separate enantiomers Select the correct statement A and C both are cyclic compounds O Compound C may be allene Compound A may be allene Compound D has less boiling point than neohexane

The enthalpy of combustion of carbon hydrogen and sucrose are 393 5 286 2 and 56442 kJ mol respectively Calculate the enthalpy of formation of sucroso 1 3 4 6323 9 kJ 2226 kJ 2226 kJ can t predict

Which of the following combinations of chemicals makes a buffer Mark all that apply Identifying solutions as buffers on a quiz or exam is a critical skill For this chapter many problems ask you to find the pH of a solution The challenge is classifying the solution appropriately and then selecting the right approach to finding its pH roughly equimolar mixture of acetic acid and sodium acetate solution that is 0 1 M each in hydrochloric acid and sodium chloride solution made by combining 25 mL of 0 1 M acetic acid with 12 5 mL of 0 1 M sodium hydroxide solution that is 0 1 M each in ammonia and ammonium chloride