Surface chemistry Questions and Answers

On adding AgNO3 solution to KI solution a negatively charged colloidal sol will be formed in which of the following conditions 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 KI 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

A 50 by 50 cm square vertical plate is maintained at 95 C and exposed to saturate steam at 1 atm pressure Calculate the amount of steam condensed per hour Calculate the ate of ond 1

A mixture of 100 m mol of Ca OH 2 and 2 g of sodium sulphate was dissolved in water and the volume was made up to 100 mL The mass of calcium sulphate formed and the concentration of OH in resulting solution respectively are Molar mass of Ca OH 2 Na SO4 and CaSO4 are 74 143 and 136 g mol respectively Ksp of Ca OH is 5 5 x 10 6 JEE Main 2019 2 13 6 g 0 28 mol L 1 4 1 9 g 0 28 mol L 1 1 1 9 g 0 14 mol L 1 3 13 6 g 0 14 mol L 1 visi

Which of the following is wrong in case of Langmuir adsorption isotherm Option A B C D It is theoretically based on kinetic theory of gases Langmuir assumed that every adsorption site is not equivalent Rate th Ability of particle to bind adsorption site is independent of near by site wheth or not Langmuir adsorption isotherm does not work well for chemisorption ution it is occup

Among the following the INCORRECT statement about colloids is The range of diameters of A colloidal particles is between 1 and 100 nm B The osmotic pressure of a colloidal solution is of higher order than the true solution at the same concentration C They can scatter light D They are larger than small molecules and have high molar mass

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 Question Type Single Correct Type 1 2 3 4 0 03 mg 30 mg 0 30mg 3 mg

Which one of the following characteristics is associated with adsorption Question Type Single Correct Type 1 AG is negative but AH and AS are positive 2 AG AH and AS all are negative 3 A AG and AH are negative but AS is positive AG and AS are negative but AH is positive

Sol 1 Al O3 xH O Sol 2 CdS Sol Sol 3 TiO Sol Sol 4 Haemoglobin Consider the following statements S In electrophoresis the dispersed phase of only two of the given sols will move towards cathode S2 In electrophoresis the dispersion medium of only three of the given sols will move towards anode S3 Only three of given sols can be precipitated by K4 Fe CN 6 Which of the following options contain only the incorrect set of statement s Only S Only S and S3 Only S2 and S3 Only So

Colloids with liquid as dispersed phase and dispersion medium are called as emulsion Identify the correct statement O Oil in water emulsion are very stable The emulsifying agent forms an interfacial film between suspended particle and the medium Any amount of dispersed phase can be O added to emulsion to concentrate it without forming a separate layer The droplets in emulsion must be positively charged

147 In freundlich adsorption isotherm the value of 1 n is A between 0 and 1 in all cases B between 2 and 4 in all cases C 1 in case of physical absorption D 1 in case of chemisorption

Which mixture of the solutions will lead to the formation of negatively charged colloidal Agl sol Question Type Single Correct Type 1 2 3 4 50 mL of 1 5 M AgNO3 50 mL of 1 5 M KI 50 mL of 1 M AgNO3 50 mL of 2 M KI 50 mL of 2 M AgNO3 50 mL of 1 5 M KI 50 mL of 0 1 M AgNO3 50 mL of 0 1 M KI

7 Select the correct observation in the following isotherm where amount of the adsorbate adsorbed per gram of the adsorbent 1 2 m 3 m X X m x O X Y Pressure P Desorption may start along XY X m 4 All of the above p when point X is reached p along OX

69 The rate of oxidation of oxalic acid by acidified potassium permanganate is shown in the given graph 10 Rate Time 5H C 0 2KMnO 3H SO 2MnSO K SO 10CO 8H O The type of catalyst shown by such reaction is 1 heterogeneous catalysis 2 induced catalysis 3 auto catalysis 4 negative catalysis Chlarinetic

To 100ml of 0 1MCH COOH 0 2g of activated charcoal is added and shaken vigorously On settling down the conc of CH COOH is found out to be 0 05M Then the mass of CH COOH adsorbed per gram of activated charcoal is A 0 3 g B 1 5 g C 0 6 g D 1 8 g

Two parallel disks 50 cm in diameter are separated by a distance of 12 5 cm and enclosed by a large room at 300 K One disk is maintained at a constant temperature of 800 C and has an emissivity of 0 8 The other disk is perfectly insulated and has an emissivity of e 0 1 Calculate the net radiant energy lost by the disk maintained at 800 C

The solubility of carbon dioxide gases in Coke is highest at OA low temperature and high pressure OB low temperature and low pressure OC high temperature and high pressure O D high pressure temperature is immaterial OE high temperature and low pressure

X 5 1 mark Freundlich adsorption isotherm is given by k pn If the graph of m X m against P has a slope k what is the value of n

The volume of gases NH3 CO2 and H adsorbed by one gram of charcoal at 300 K are in order of Question Type Single Correct Type 1 H2 CO2 NH3 2 NH3 H2 CO2 3 NH3 CO2 H2 4 CO2 NH3 H2

Consider the following statements a A molecule in the bulk of liquid experiences equal intermolecular forces from all sides b Molecules of a liquid on the surface have more energy than the molecules in the bulk c The highest energy state of the liquid will be when surface area is minimum The correct statements is are O a only Ob only O a and b only a b and c

The decomposition of phosphine PH3 on tungsten at low pressure is a first order reaction It is because the 1 rate is independent of the surface coverage 2 rate of decomposition is very slow 3 rate is proportional to the surface coverage 4 rate is inversely proportional to the surface

5 The molar heat of vaporization of water is 42 kJ mol How much energy is released by the condensation of 3 0 g of water 1 mark a 0 88 kJ b 7 0 kj c 126 kJ d 130 kJ 6 An equilibrium that strongly favors products has 1 mark a a value of Q 1 b a value of K 1 c a value of Q 1 d K Q 7 Consider the reaction CH4 g 202 g CO2 g 2H2O g find the numbers instead of the letters a to g each 1 mark CH 0 5 0 0 5 CO 10 10 H O

Which is incorrect regarding plasma level curve Select one a Therapeutic range should be lower than MEC O b Absorption phase comes first then Elimination phase Oc Plot of plasma concentration with time d Absorption phase end at maximal drug level obtained with de

hydrated 7 Which one of the following statements is not correct in respect of lyophilic sols a There is a considerable interaction between the dispersed phase and dispersion mediu b These are quite stable and are not easily coagulated c They carry charge d The particles are hydrated

4 Among the following colloids the num ber of colloids having negatively charged colloidal particles is Soap solution of sodium palmitate sol of AgCl obtained on dissolving excess AgNO into KCl solution gold sol Fe OH sol silicic acid sol Basic dye Acidic dye metal sulphide sol sol of AgCl obtained by dissolving excess KC1 in AgNO solution ANSWER

Select the incorrect option s amongst the following A Gold sol is a positive charged sol B Lyophobic sols can act as protective colloid for Lyophilic sols C When FeCl is hydrolysed with hot water then ferric hydroxide sol positiv charged will be obtained D Colour of colloidal solution depends on size shape of dispersed phase

Which of the following is incorrect match A B C physisorption multilayered Active Adsorption Requires activation energy Lyophobic colloid charge is present

a b c d List I Cyanide process Floatation process Electrolytic reduction Zone refining List II 1 Ultrapure Ge 2 Pine oil 3 Extraction of Al 4 Extraction of Au 1 a 3 b 1 c 4 d 2 2 a 4 b 2 c 3 d 1 3 a 3 b 2 c 4 d 1

2 3 1 g of dry green algae absorbs 4 7 x 103 mole of CO per hour by photosynthesis If the fixed carbon atoms were all stored after photosynthesis as starch C6H 0 05 how long would it take for the algae to double their own 7 88 hours weight assuming photosynthesis takes place at a constant rate

1 Ethyl chloride 2 Isopropyl chloride 3 CI On of the processes used for concentration of ores is Froth floatation process This process is generally used for concentration of sulphide ores Sometimes in this process we add NaCN as a depressant NaCN is generally added in case of ZnS and PbS minerals What is the purpose of addition of NaCN during the process of Forth floatation 1 NaCN causes reduction by precipitation 2 A soluble complex is formed by reaction between NaCN and ZnS while PbS forms froth 3 A soluble complex is formed by reaction between NaCN and PbS while ZnS forms froth 4 A precipitate of Pb CN is produced while ZnS remain unaffected Which fah

64 Which of the following graph represents the variation of amount of chemisorption of a gas by a solid with temperature under constant pressure 3 x m IS xm

r is is of gy 41 A gas is collected by downward displacement of water Select the correct expression for p according to figure d 13 6 g cm Hg b Pas Gas H O d 1 g cm h a Pgas Patm Aqueous tension 13 6 Palm hdg cm C Pgas Patm Aqueous tension X d None of these h 13 6

LE 2 21 CNS ions give red colour with Fe3 ions in aqueous solution as Fe aq 3CNS aq Fe CNS 3 aq red If 0 1 M KCNS solution is separated from 0 1 M FeCl solution by means of a semi permeable membrane red colour will appear on a FeCl solution c Both sides 3 b KCNS solution side d Neither side

3 Two students X and Y report the mass of the same substance as 7 0 g and 7 00 g respectively which of the following statement is correct a Both are equally accurate b X is more accurate than Y c Y is more accurate than X d Both are inaccurate scientifically

2 012 1020 photons per second Example 11 Calculate the maximum kinetic energy of photoelectrons emitted when a light of frequen 2 x 1016 Hz is irradiated on a metal surface with threshold frequency v equal to 8 68 x 1015 H olution hv hvo KE Threshold frequency vo 8 68 x 1015 Hz s Frequency of light v 2 1016 Hz KE h v v 6 626 10 34 2 x 1016 8 68 x 10 5 KE 7 5 x 10 18 J Maximum kinetic energy of photoelectrons 7 5 10 18 J

Spontaneous adsorption of gas on solid surface is an exothermic process because Question Type Single Correct Type 1 Enthalpy increases for system 2 Entropy increases for gas 3 Entropy decreases for gas

U m the 32 If K and K are maximum kinetic energies of mitted photoelectrons emitted when lights of wavelength and respectively incident on a metallic surface 13 then a K K 3 c K 3K n the b K K 3 d K 3K

positive and negative negative and positive positive and positive negative and negative Question Type Question ID Option 1 ID

1 9 03 10 2 3 01x10 3 6 02x10 A micelle formed during the cleansing action by soap is 1 a discrete particle of soap 3 a discrete particle of dust 4 1 8x10 2 aggregated particles of soap and dirt 4 an aggregate particle of dust and water

Which of the following will have highest coagulating power for As S3 colloid a Po c A1 b so d Na

Q 1 Solve the following multiple choice questions 1 Varnish is used to give A Transparent finish B Red colour finish C Opaque finish D Fire resistant finish 2 Thinners are added to paint to A Improving drying quality B Reduce the cost C Reduce the consistency D Provide water proofness Record 3 The paint is a mechanical dispersion mixture of one or more A Resin B Polymer C Pigment D Monomer O istr screenshot in a vehic

Which of the following is correct statement regarding zeolite O Size of pores is approximately 300nm 700nm O Zeolite is 2 D silicate O Zeolite is sodium alumino silicate O Zeolite is used as catalyst in hydrolysis of ester FADER 27

Which of the following is not correct energy is an extensive a Gibbs property b Electrode potential or cell potential is an intensive property c Electrical work AG d If half reaction is multiplied by a numerical factor the corresponding E value is also multiplied by the

Calculate the surface area per gm of a catalyst that adsorb 1000 ml of N gas at STP to form a monolayer at their surface Surface area of a N molecule is 1 62 10 5 cm 2200ML 1000 L 1 4 35 cm 2 4 35 x 107 m 3 4 35 x 107 cm 2 2 4 435 cm foluemulsion

0 Which of the following has minimum protecting power 1 Gelatin Gold no 0 01 2 Dextrin Gold no 15 3 Potato starch Gold no 25 4 Albumin Gold no 0 25

derstanding The pKa of HNO2 is 3 37 The pH of HNO2 in its 0 01 mol L 1 aqueous solution will be 1 5 37 2 2 69 3 1 69 4 0 69

2 In an experiment addition of 4 0 mL of 0 005 M BaCl to 16 0 mL of arsenius sulphide sol just causes complete coagulation in 2 hrs The flocculating value of the effective ion is 900 2014 Dolnoy a Cl 1 0 c Ba 1 0 70 000 b Cl 2 0 d Ba 0 5 200 0 s 2 0 s 01 000 0 A For a gas solid adsorbent system the adsorption isotherm

Calculate the volume at 300 K at 1 atm and amount adsorbed per g of 2g solid surface if 4g of N is allowed to adsorbed at 300 K and 0 8 atm 1 2 5 litre g 2 3 2 litre g 3 1 76 litre g 4 5 62 litre g

58 X 1 501 5 50 Which mixture of the solutions will lead to the formation of negatively charged colloidal AgI Isol a 50 of 0 1 M AgNO3 50 mL of 0 1 MKT b 50 mL of 1 M AgNO3 50 mL of 1 5 M KI c 50 mL of 1 M AgNO3 50 mL of 2 M KI d 50 ml LO 5

A freshly prepared Fe OH precipitate is peptized by adding FeCl solution The charge on the colloidal particles is due to preferential adsorption of 1 Cl ions 3 OH ions 2 Fe ions 4 None

Medicines are more effective if they are used in 2 Solid state 4 All of the above 1 Colloidal state 3 Granular state