Surface chemistry Questions and Answers

0 X Graph between log and log p is a straight line at an angle 45 with intercept on y axis 0 3010 of Calculate the amount of gas adsorbed in gram per gram of the adsorbent when pressure is 0 2 atm 1 0 4 2 0 6 4 0 2 3 0 8 m

03 Addition of lyophilic solution to the emulsion forms a a protective film around the dispersed phase b a protective film around the dispersion medium c an aerosol d true solution 16 or

7 Air can oxidize sodium sulphite in aq solution but cannot do so in the case of sodium arsenite If ids however air is passed through a solution containing both sodium sulphite sodium arsenite then bot are oxidized This is an example of 1 Positive catalysis 2 Negative catalysis 4 Auto catalysis 3 Induced catalysis

Lyophilic colloidal solution can be coagulated by 1 addition of high concentration of electrolyte 2 By addition of solvent like C H OH 3 By addition of excess H O 4 Both 1 2 correct

4 As S3 colloidal solution obtained when As O3 is saturated with H S Which is the diffused part belliso e Hq bla 1 As 3 2 S Jnioq br S og monte alls must 4 0 3 H

61 Which pair is correctly matched Fe OH Fe CH 2 As S As 3 SnO SnO in acidic medium 4 Agl It in excess of AgNO3

Which is are correct about protective colloids 1 Haemoglobin cannot be used as a protective colloids 2 Protective colloids are responsible for the stability of paints ink etc 3 Lyophobic colloids act as protective colloids 4 Gelatin is a better protective colloid than gum proble

Some of the following sluI Air inte at III Glucose solution V Pearl Select true solutions 1 I II III 3 I IV V VI are true solutions II Sea water IV Gem stone VI Blood 2 II III IV V 4 II IV VI 9

c no charge The gold numbers of protective colloids A B C and D are 0 04 0 004 10 and 40 respective The protective powers of A B C and D are in the order A A B C D b B A C D C D C A B d D C B A Rist In Brownian motion the paths of the particles are red

67 A sample of 16 g charcoal was brought into contact with CH4 gas contained in a vessel of nude 1 litre at 27 C The pressure of gas was found to fall from 760 to 608 torr The density of charcoal sample is 1 6 g cm The volume of the CH gas adsorbed per gram of the adsorbent at 608 torr and 27 C is mL g Assume initially vessel has CH gas only

7 Which of the following will have the highest coagulating power for Fe OH 3 colloid 3 2 b SO2 4 c Ca d Al3 Artificial rain is caused by spraying a PO

Express the Rydberg constant R 109678 cm a J atom b J mol

27 Predict conditions under which Al might be expected to reduce MgO Hint See Intext question 6 4

A long cylindrical conductor of radius R contains current of uniform density J Two small holes of radius r R 2 are drilled symmetrically throughout the length of the cylinder The axes of the holes are parallel to the axis of cylinder and at distance d from it in the same plane Magnetic field on the axis of one of the hole will be Mi 2 7 2 10 0 1 B 14 20 2nd R 2 A Hod 2 C Hod 2 d 2d B D none of the above 0

178 Which of the following electrolytes is most effective in coagulation of gold sol SiC14 2 K4 Fe CN 6 AICI3 3 Na3PO4 o the following in the order of decreasing

4 Gamma potential 19 The maximum power to precipitate arsenious sulphide is of 1 H SO 4 2 Na3 PO4 man h 3 CaCl 4X AICI LAX

A 0 016 M of an acid solution in benzene is dropped on a water surface the benzene evaporates and the acid forms a monomolecular film of solid type What volume of the above solution would be required to cover a 500 surface area of water with monomolecular layer of acid Area covered by single acid molecule is 0 2 24 94 x 10 ml B 25 94 x 10 ml Correct Answer 3 67 x 10 3 ml 06

147 Which of the following molecules is most suitable to disperse Daba benzene in water a Nexsus or c BMJ 3129 b Nat O ods 25midreuo O Nat O sortuod rdslieve zi cis aydate di a 6011 lor O Nat c CH3 AV

68 Which gas would get adsorbed when passed into a solution of A1 aq a NH b NO c CO stafton 4 d 0

One desires to prepare a positively charged sol of silver iodide This can be achieved by AC Ag ingen a adding a little AgNO solution to KI solution in slight 3 shi 3Tuners an 3 excess b adding a little KI solution to AgNO solution in slight ved cemper 201 3 10 07 excess 5265 10 NOT and KI ne fol a artis outdo d none of these c mixing equal volumes of equimolar solutions of AgNO I on AgNo 1 AgI KNO 9 203 o ghar pogl

On adding AgNO3 solution into KI solution a negatively charged colloidal sol is obta when they are in a 50 mL of 0 1 M AgNO3 50 mL of 0 1 M KI b 50 mL of 0 1 M AgNO3 50 mL of 0 2 M KI c 50 mL of 0 2 M AgNO3 50 mL of 0 1 M KI d None of these 1000 of AgNO solution in KI solution The charge likely to

On adding few drops of dil HCl to freshly precipitated ferric hydroxide a red colored colloidal solution is obtained This phenomenon is known as many box a peptisation b dialysis c protective action d dissolution 34

22 Coagulating power of NaCl and AlCl is 51 and 0 093 respectively AlCl coagulates x times faster than NaCl The value of x is a 530 b 565 1 of c 548 isted d 570 E minde har Id

3 36 The coagulation values of AICI and NaCl are 0 093 and 52 respectively Then coagulating power of AICI as compared to that of NaCl is a 52 x 0 093 times b 52 0 093 times c 0 093 52 times d None of these

Tyndall effect is observed only when i the diameter of the dispersed particles is not much smaller than the wavelength of the light used ii the refractive indices of dispersed phase and dispersion medium differ greatly in magnitude iii the size of the particles is generally between 10 11 and 10 m in diameter iv the dispersed phase and dispersion medium can be seen separately in the system b i and iv a i and iii c ii and iii d i and ii

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

The gold number of gelatin is 0 01 Calculate the amount of gelatin in mg to be added to 1000 mL of a colloidal sol of gold to prevent its coagulation before adding 1 mL of 10 NaCl solution

In an experiment addition of 4 0 mL of 0 005 M BaCl to 16 0 mL of arsenious sulphide sol just causes the complete coagulation in 2 h The flocculating value of the effective ion is

A Which of the following options are correct Cast iron is obtained by remelting pig iron with scrap iron and coke using hot air blast In extraction of silver silver is extracted as cationic complex Nickel is purified by zone refining Zr and Ti are purified by van Arkel method B C D

ne The following statements relate to adsorption of gases on a solid surface Identify the incorrect statement among them 2 1 Enthalpy of adsorption is negative Entropy of adsorption is negative On adsorption the residual forces on the surface are increased 3 4 On adsorption decrease in surface energy appears as heat

41 It converts alcohols directly into gasoline by dehydration It is 42 a zeolite S c ZSM 5 An ultro filton ai b zeolite A stodola 16 d d chabazite ib 19tew 3 vodne to anng h

In an experiment addition of 5 0 mL of 0 006 M BaCl to 10 0 mL of arsenic sulphite sol just causes the complete coagulation in 34 h The following value of the effective ion is

76 When an excess of a very dilute aqueous solution of KI is added to a very dilute aqueous solution of silver nitrate the colloidal particles of silver iodide are associated with which of the following Helmholtz double layer a Agl Agt r b Agl K NO 3 c AgI NO Agt d Agl I K 3

3 On adding AgNO solution to KI solution a negatively charged colloidal sol will be formed in which of the following conditions AgNO3 Kro Ag I K NO a 100 mL of 0 1 M AgNO3 100 mL of 0 1 M KI b 100 mL of 0 1 M AgNO3 50 mL of 0 2 M KIY c 100 mL of 0 2 M AgNO3 100 mL of 0 1 M KI d 100 mL of 0 1 M AgNO3 100 mL of 0 15 M KI

The coagulation of 100 mL of a colloidal sol of gold is completely prevented by addition of 0 03 g of Haemoglobin to it before adding 1 mL of 10 NaCl solution Calculate the gold number of Haemoglobin

d Iragmentation 65 The method usually employed for the destruction of a colloidal solution is a dialysis b addition of electrolytes c diffusion through animal membrane d condensation

00 Which of the following methods is used for the destruction of sol a Condensation to sigrasxo Dialysis 1725 458 c Diffusion through animal membrane a pag 3 d Addition of an electrolyte aib belus

18 There is no scum formation when hard water is being used The washing powder can be 310 sidh a C HCOONa rozd b R O Ves c both of these SO Na RockT d none of these

a Nig 15 x m OV temperature constant 612975031 rigid at tai 29 Boob P x m 31 G temperature constant B P A Which is correct statement a A represents Freundlich s adsorption isotherm while B represents Langmuir s adsorption isotherm b A represents Langmuir s adsorption isotherm while B represents Freundlich s adsorption isotherm c Both Freundlich and Langmuir adsorption isotherms have been found to be applicable in the adsorption of gases on solids only WOLFARIN d Change of pressure affects a lot and further adsorption

In homogeneous catalysis the rate of reaction depends upon the a concentration of catalyst surface area of catalyst LOTURO c physical state of the catalyst d all of these 8 beisgold or les are as he trebbe tenaque B B Gelos labiellus sbinglu SrasmA IT

b Explain why the Langmuir model describes Chemisorption better than Physisorption c The adsorption of a gas is described by the Langmuir isotherm with K 0 3 kPa Calculate the fractional coverage at a pressure 0 2 kPa Continued 369 5 4

In colloids particles showing zigzag mo vements are stablized by repulsion due to similar charged particle and do not p recipitate But in case of true solutions the is no electrolyte but still the particle s are not precipitated How

The volume of N gas calculated at S T P is required to cover a sample of silica gel with a monomolecular layer is 610 cc for 5 gram of the gel Calculate the surface area of the gel if the nitrogen gas has a density of 0 03 gram cc at S T P

A substance will be deliquescent if its vapour pressure 1 Is equal to the atmospheric pressure 2 Is equal to that of water vapour in air 3 Is less than that of water vapour in air 4 Is greater than that of water vapour in air

3 cuce Which of the following is not a characteristic pro the polar liquids They have high boiling points 2 They have high heat of evaporation 3 They have low viscosity

using the data in the graphs determine the gibbs free energy entropy and enthalpy for the mechanical stretching data graphs thanks Mass kg Mass kg 0 141 0 14 0 139 0 138 0 137 0 136 0 135 305 0 082 0 0815 0 081 0 0805 0 08 0 0795 y 0 0002x 0 0805 R 0 9895 310 Rubber Band Elastomer Box 305 310 315 y 6E 05x 0 0996 R 0 9966 315 y 0 0002x 0 081 R 0 986 320 Temperature K 325 Spring Box 320 y 7E 05x 0 1032 R 0 986 325 330 y 0 0002x 0 0807 R 0 9834 330 335 y 6E 05x 0 1004 R 0 991 335 Trial S Trial 6 Trial 7 Linear Trial 5 Linear Trial 6 Linear Trial 7 Trial 4 Trial 5 Trial 6 Linear Trial 4 Linear Trial 5 Lincar Trial 6

0 1 g of animal charcoal is mixed with 0 25 litres of 0 2 M CH COOH solution If the extent of adsorption 1 m on animal charcoal is 2 then the final molarity of the CH COOH solution left is 1 0 053 M 3 0 196 M 2 0 186 M 40 083 M

Supply the missing data in the table below Also determine the FREUNDLICH isotherm constants for the following adsorption test data The liquid volume used in the batch adsorption tests was 1 Liter Mass of Adsorbent Original Concentration of Adsorbate grams in Solution mg L 0 3 45 0 001 0 010 0 100 0 500 3 45 3 45 3 45 3 45 Equilibrium Concentration of Adsorbate in Solution mg L 3 45 3 20 2 81 1 76 1 25 Weight of substance adsorbed mg A B C D E

10 g of gelatin is required to be added to 10 cm of a standard gold sol to just prevent its coagulation by the addition of 1 cm of 10 NaCl solution to it Hence the gold number of gelatin is 1 10 2 1 0 3 0 1 4 0 01

The potential difference between the fixed charged layer and the diffused layer having opposite charge is called O Zeta potential O Electrokinetic potential O sedimentation potential 1