InterviewSolution
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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 101. |
Why does bleeding stop by rubbing moist alum? |
| Answer» Blood is a colloidal sol. When we rub the injured part with moist alum then coagulation of blood takes place. Hence, main reason is coagulation, which stops the bleeding. | |
| 102. |
Bleeding is stopped by the application of ferric chloride. This is becauseA. The blood starts flowing in the opposite directionB. The blood reacts and a solid is formed which seals the blood vesselC. The blood is coagulated and the blood vessel is sealedD. The ferric chloride seals the blood vessel |
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Answer» Correct Answer - C `Fe^(+3)` ion coagulates -ve sol particles of blood and seals the cut. |
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| 103. |
Which of the following ielectrolytes is least effective in causing flocculation of ferric hydroxide sol?A. `K_(4)[Fe(CN)_(6)]`B. `K_(2)CrO_(4)`C. `KBr`D. `K_(2)SO_(4)` |
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Answer» Correct Answer - C KBr is least effective in causing flocculatio of ferric hydroxide sol due to minimum charge at (KBr) `Br^(-)`. |
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| 104. |
The arsenious sulphide sol has negative charge . The maximum coagulating power for precipitiating it is of :A. ` 0. 1 N Zn (NO_3)_2`B. `0. 1 N Na_3 PO_4`C. ` 0. 1 N Zn SO_4`D. `0. 2 N Alcl_3` |
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Answer» Correct Answer - D More is the valence of effective ion, greater is its coagulating power . The Hardy-Schulze rule. |
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| 105. |
Bleeding is stopped by the application of ferric chloride. This is becauseA. the blood starts flowing in opposite directionB. the blood reacts and forms a solid, which seals the blood vesselC. the blood is coagulated and thus the blood vessel is sealedD. the ferric chloride seals the blood vessel. |
| Answer» Correct Answer - C | |
| 106. |
An arsenious sulphide sol carries a negative charge the maximum precipitating power fo this sol is possessed byA. `K_(2)SO_(4)`B. `CaCl_(2)`C. `Na_(2)PO_(4)`D. `AlCl_(3)` |
| Answer» Correct Answer - 4 | |
| 107. |
Ferric chloride is applied to stop bleeding cut becauseA. `Fe^(3+)` ion coagulates blood, which is a negatively charged sol.B. `Fe^(3+)` ion coagulates blood, which is a positively charged sol.C. `Cl^(-)` ion coagulates blood, which is a positively charged sol.D. `Cl^(-)` ion coagulates blood, which is a negatively charged sol. |
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Answer» Correct Answer - A `FeCl_(3)` is an electrolyte give `Fe^(3+)` and blood contain negatively colloid so stop bleeding due to coagulation. |
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| 108. |
An arsenious sulphide sol carries a negative charge . The maximum precipitating power for this sol is possessed byA. `K_(2)SO_(4)`B. `CaCl_(2)`C. `Na_(3)PO_(4)`D. `AlCl_(3)` |
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Answer» Correct Answer - D Higher the valency maximum precipiating power for this sol. |
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| 109. |
`50 mL` of standard gold solution needs `0.05 mg` of gelatin for its protection from coagulation. Calculate the gold number of gelatine? |
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Answer» `50mL` of standard gold sol requires `=0.05mg` of gelatin Therefore, `10mL` of standard gold sol requires `=(0.05)/(50)xx10=0.01mg` of gelatine `:.` Gold number `=0.01` `50mL` of standard gold sol requires `=0.05mg` of gelatin Therefore, `10mL` of standard gold sol requires `=(0.05)/(50)xx10=0.01mg` of gelatine `:.` Gold number `=0.01` |
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| 110. |
For the coagulation of `500mL` of arsenious sulphide sol, `2mL` of `1MNaCl` is required. What is the flocculation value of `NaCl` ? |
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Answer» Correct Answer - 4 2mL of 1M NaCl contains `NaCl=(2)/(1000)=2` mmol Thus 500 mL of `As_(2)S_(3)` sol require NaCl for complete coagulation=2mmol Hence 1L, i.e., 1000 mL of the sol reqruie NaCl for complete coagulation=4mmol Therefore, flocclation value of NaCl=4 |
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| 111. |
`SnO_(2)` forms positively charged colloidal sol in acidic medium and negatively charged colloidal sol in basic medium. Explain ? |
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Answer» `SnO_(2)` is amphoteric reacting with acid and base both. In acidic medium (say HCl) `Sn^(4+)` ion is formed which is preferentially adsorbed on `SnO_(2)` giving positively charged colloidal sol : `SnO_(2) + 4HCl to SnCl_(4) + 2H_(2)O ,` `SnO_(2) + SnCl_(4) to [SnO_(2)]Sn^(4+)` (Positively charged) `+ 4Cl^(-)`. |
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| 112. |
In the lower layer of the atmosphere, there is great deal of dust. When the weather is fine, it is possible to see the magnificent red colour of the setting sun. What have these observation to do with colloids ? |
| Answer» Dust in the atmosphere is often colloidal. When the sun is low down on the horizon, light from it has to pass through a great deal of dust to reach your eyes. The blue part of the light is scattered away from your eyes. You see the red part of the spectrum, which remains. Red sunsets are the Tyndall effect on a large scale. | |
| 113. |
How are lyophobic solutions protected from phenomenon of coagulation. |
| Answer» Lyophobic sols are protected from the phenomenon of coagulation by adding suitable lyophilic sol. | |
| 114. |
Which of the follwing colloids are formed when hydrogen sulphide gas is passed through a cold solution of arsenious oxide?A. `As_(2)S_(3)`B. `As_(2)O_(3)`C. `As_(2)S`D. `As_(2)H_(3)` |
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Answer» Correct Answer - A It is due to adsorption of `S^(2+)` ions on the surfaces of the colloidal particles and `H^(+)` ions in the diffused layer. |
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| 115. |
Which of the follwing colloids are formed when hydrogen sulphide gas is passed through a cold solution of arsenious oxide?A. `As_(2)S_(3)`B. `As_(2)_(3)`C. `As_(2)S`D. `As_(2)H_(2)` |
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Answer» Correct Answer - A It is due to adsorption of `S^(2-)` ions on the surface of the colloidal particles and `H^(+)` ions in the diffused layer. |
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| 116. |
Classify the following sols according to their charges : (a) gold sol (b) ferric hydroxide sol (c) gelatine (d) blood (e) sulphur (f) arsenious sulphide (g) titanium oxide. |
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Answer» Negatively charged colloidal sol : (a), (c), (d), (e), (f). Positively charged colloidal sol : (b), (g). |
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| 117. |
For coagulation of arsenious sulphide sol, which one of the following salt solution will be most effective ?A. `Na_(3)PO_(4)`B. `AlCl_(3)`C. `BaCl_(2)`D. `NaCl` |
| Answer» Correct Answer - B | |
| 118. |
Precipitation occurs when hydrated ferric oxide and arsenious sulphide are mixed. It is due toA. ElectroosmosisB. ElectrophoresisC. CatalysisD. Mutual coagulation |
| Answer» Correct Answer - D | |
| 119. |
Coagulation takes place when sodium chloride solution is added to a colloidal solution of hydrated ferric oxide. Explain. |
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Answer» When NaCI solution is added to the colloidal solution of hydrated ferric oxide coagulation takes place (precipitation formed). `to` The reason is that colloidal particles interact with ions `(Na^(+), Cl^(-))` carrying charge opposite to that present on themselves. This causes neutralisation of charges leading to their coagulation. |
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| 120. |
How many of the following may cause coagulation in colloidal solutions? (a) Tanning (b) Dialysis (c ) Cataphoresis (d) Mixing of a lyophilic sol with a lyophobic sol (e) Mixing of two lyophobic sols (f) Mixing sol-I (`AgNO_(3)` with excess KI) and sol-II (KI with excess `AgNO_(3)`) (g) Addition of alcohol to a hydrophilic sol followed by addition of small quantity of electrolyte (h) Centrifuging (i) Freezing |
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Answer» Correct Answer - 9 |
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| 121. |
If a strong beam of light is passed through a colloidal sol place in a dark space, the part of the beam gets illuminated. This phenomenon is calledA. Tyndall effectB. Brownian effectC. Dorn effectD. Hardy-Schulze effect |
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Answer» Correct Answer - A If a homogeneous solution placed in dark is observed in the direction of light, it appears cler (i.e. we are able to trace out the path of light). But if it is observed from a direction at right angles to the direction of light beam, it appears perfectly dark, Colloidal solutions viewed is the same way also appear reasonbly clear or translucent by the transmitted light but they show a mild to strong opalescence, which viewed at right angles to the passage of light i.e. the path of the beam is illuminated by a coloured light. This effect was first observed by Faraday and later studied in detail by Tyndall and is therefore termed as Faraday-Tyndall effect or just Tyndall effect, The illuminated path of beam (the bright cone of the light) is called Tyndall cone. |
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| 122. |
Explain the phenomenon observed An eleetrlc current is passed through a colloidal solution. |
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Answer» Electrophoresis : The existence of charge on colloidal particles is confirmed by electrophoresis experiment. When electric potential is applied across two platinum electrodes dipping in a colloids solution, the colloidal particles move towards one or the other electrode. The movement of colloidal particles under an applied emf is called "electrophoresis". `to` Positive charged particles move towards the cathode while negative charged particies towards anode. |
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| 123. |
Mildness of shaving cream is enriched by which one of the following ?A. LiquidB. GasC. SolidD. None of these |
| Answer» Correct Answer - A | |
| 124. |
Whipped cream is an example ofA. `{:("Dispersion medium","Dispersed phase"),((a)" Gas","Liquid"):}`B. `{:("Dispersion medium","Dispersed phase"),((a)" Liquid","Gas"):}`C. `{:("Dispersion medium","Dispersed phase"),((a)" Liquid","Liquid"):}`D. `{:("Dispersion medium","Dispersed phase"),((a)" Liquid","Solid"):}` |
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Answer» Correct Answer - B `underset(("dispersion medium"))("Liquid")+underset(("Dispersed phase"))(Gas)=underset("Colloidal solution")("whipped cream")` |
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| 125. |
Flocculation value is expressed in terms ofA. milli mol `L^(-1)`B. mol `L^(-1)`C. mg `K^(-1)`D. microgram `mL^(-1)` |
| Answer» Correct Answer - A | |
| 126. |
Define flocculation value. |
| Answer» The minimum concentration of an electrolyte in millimoles per litre required to cause coagulation of a sol in two hours is called "coagulating value" (or) flocculation value. | |
| 127. |
Define "promoters" and "poisons" in the phenamenon of catalysis ? |
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Answer» Promoters : The substances with enhance the activity of catalyst are known as promoters. Poisons : The substances which decrease the activity of a catalyst are known as poisons. |
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| 128. |
Comprehension # 1 Many lyophilic sols and few lyophobic sols when coagulated under some special conditions changes into semi rigid mass, enclosing whole amount of liquid within itself, it is called gel and the process is called gelation, Gelatin Agar-agar, gum-Arabic can be converted into gels by cooling them under moderate concentration conditions. Hydrophobic sols like silicic acid. `Al(OH)_(3)` are prepared by double decomposition and exchange of solvent method. Types of Gel : (i) Elastic gel : Those gel which have elastic properties. Ex : Gelatin, Strach, Agar-agar etc. (ii) Non-elastic gel : Those gel which are rigid. Ex : Silica gel. Properties of Gel : 1. Syneresis/weeping of gel : The spontaneous liberation of liquid from a gel is called syneresis or weeping of gels. It is reverse of swelling. Ex : Gelatin, Agar-Agar show syneresis at low concentration while sillicic acid shows it at high concentration. 2. Imbibition or swelling of gel : When gel is kept in a suitable liquid (water) it absorb large volume of liquid. The phenomenon is called imbibition or swelling of gel. 3. Thixotropic : Some gels when shaken to form a sol, on keeping changes into gel are termed as thixotropic gel and phenomenon is called thixotropy. Ex : Gelatin and silica liquify on shaking changing into corresponding sol and sol on keeping changes back into gel. The process of imbibing water when elastic gel are placed in water is called :A. imbibitionB. synersisC. coagulationD. thixotropy |
| Answer» Correct Answer - A | |
| 129. |
Comprehension # 1 Many lyophilic sols and few lyophobic sols when coagulated under some special conditions changes into semi rigid mass, enclosing whole amount of liquid within itself, it is called gel and the process is called gelation, Gelatin Agar-agar, gum-Arabic can be converted into gels by cooling them under moderate concentration conditions. Hydrophobic sols like silicic acid. `Al(OH)_(3)` are prepared by double decomposition and exchange of solvent method. Types of Gel : (i) Elastic gel : Those gel which have elastic properties. Ex : Gelatin, Strach, Agar-agar etc. (ii) Non-elastic gel : Those gel which are rigid. Ex : Silica gel. Properties of Gel : 1. Syneresis/weeping of gel : The spontaneous liberation of liquid from a gel is called syneresis or weeping of gels. It is reverse of swelling. Ex : Gelatin, Agar-Agar show syneresis at low concentration while sillicic acid shows it at high concentration. 2. Imbibition or swelling of gel : When gel is kept in a suitable liquid (water) it absorb large volume of liquid. The phenomenon is called imbibition or swelling of gel. 3. Thixotropic : Some gels when shaken to form a sol, on keeping changes into gel are termed as thixotropic gel and phenomenon is called thixotropy. Ex : Gelatin and silica liquify on shaking changing into corresponding sol and sol on keeping changes back into gel. Some types of gels like gelatin and silica liquify on shaking thereby changing into sols. The sols on standing change back into gels. This process is know asA. synersesisB. thixotropyC. double decompostionD. peptization |
| Answer» Correct Answer - B | |
| 130. |
Breding arc method cannot be used to prepare colloidal solution of which of the following ?A. `Pt`B. `Fe`C. `Ag`D. `Au` |
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Answer» Correct Answer - 2 Electrical disintegration of Bredigs are method is used for preparing colloidal solution of metal like gold silver, platinum. Etc. In this method electric arc is struck between electrodes of metal immersed in the dispersion medium. The intense heat produced vaporizes some of the metals which then condenses to form particles of colloidal size. As iron do not vaporise easily, it cannot be prepared by this method. A colloidal solution of `Au,Ag` and `Pt` can also be prepared by reducing its salt solution with suitable reducing agent. `2AuCl_(3)+3SnCl_(2)rarrunderset("Gold sol")(2Au+3SnCl_(4))` |
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| 131. |
The disperse pahse, dispersion medium and nature of colloidal solution (lyophilic or lyophobic) of gold solution respectively, are `:`A. solid, solid , lyophobicB. liquid ,liquid, lyophobicC. solid,liquid,lyophobicD. solid,liquid,lyophilic |
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Answer» Correct Answer - 3 Colloidal solution of gold is obtained when dispersed phase is solid and dispersion medium is liquid. Substances like methals cannot be brought into the colloidal state simply by bringing them in contact with water and therefore, special methods are devised for the purpose. Hence, they are known as hydrophobic or lyophobic colloids. |
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| 132. |
The most important property of lyophobic colloidal dispersion is that the colloidal particles always carry an electric change. The nature of this charge is the same on all the particles in a given colloidal solution and may be either positive or negative. Which of the following is an electronegative colloid?A. Arsenious sulphide solB. Ferric hydroxide solC. HaemoglobinD. Methylene blue |
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Answer» Correct Answer - A The dispersion medium has an equal and opposite charge making the system neutral as a whole. Due to similar nature of the charge carried by the particles, they repel each other and do not combine to form bigger particles. That is why a lyophobic sol is stable and particles do not settle down. Metallic hydroxides (or hydrated metallic oxides), some metals (such as `Bi,Pb,Fe)`, basic dyes (such as methyl violet and methylene blue) are electropositive colloids while metallic sulphides (such as `As_(2)S_(3)S,b_(2)S_(3),CdS`), many metals (such as `Cu,Ag,Au,Pt`), acidic dyes (eosin, congo red) are electronegative colloids. |
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| 133. |
Statements : The stability of lyophobic sold is lesser than lyophilic sols . Expabnations : Lyophilic sols pssess loving nature for liquid .A. if both assertion and reason are true and the reason is the correct explanation of the assertion.B. If both assertion and reason are true but reason is not the correct explanation of the assertionC. If assertion is true but reason is false.D. If the assertion and reason both are false. |
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Answer» Correct Answer - B Both assertion and reason are true but reason is not the correct explanation of assertion. If the dispersion medium is separated from the dispersed phase, the lyophilic sol can be reconstituted by simply remixing with the dispersion medium. That is why these sols are also called reversible sols. |
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| 134. |
Which colloid can be coagulated by `Al^(+3)`?A. HaemoglobinB. `TiO_(2)`C. `As_(2)S_(3)`D. CdS |
| Answer» Correct Answer - C::D | |
| 135. |
which of the following forms cationic micelles above certain concentration?A. UreaB. cetyltrimethylammonium bromideC. sodium dodecyl sulphateD. sodium acetate |
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Answer» Correct Answer - D Sodium acetate forms cationic micelles in the molecule of soap and detergen the negative ions aggregate to from a micelle of colloidal size . The negative ion has a long hydrocarbon chain and a polar group `(-COO)` at one end. |
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| 136. |
which of the following forms cationic micelles above certain concentration?A. Sodium ethyl sulphateB. Sodium acetateC. UreaD. Cetyl trimethyl ammonium bromide |
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Answer» Correct Answer - D Cetyltrimethylammonium bromide forms cationic micelles above a certain concentration. In the molecule of detergents and soap, the negative ions aggregate to form a micelle of colloidal size. In polar medium (like water), the negative ion has a long hydrocarbon chain and a polar group `(-COO^(-))` at one end and on other end, it has `N^(+)` ion, thus cationic micelle is formed. |
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| 137. |
Which of the following forms cationic micelles above certain concentration ?A. Sodium dodecyl sulphateB. UreaC. Sodium acetateD. Cetul trimethyl ammonium bromide |
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Answer» Correct Answer - D `R(NH_3)_(3) Br rarr R (NH_3)_(3)^(+) + Br` Alkyl trimethyl amonium ion aggregates to form cationci micelle. |
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| 138. |
The coagulation of sol particles may be brought in by :A. boilingB. persistent dialysisC. adding electroyteD. adding oppositely charged sol |
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Answer» Correct Answer - a,b |
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| 139. |
Which is (rarr) not lyophobic in nature ?A. GelationB. sulphurC. StarchD. Protein |
| Answer» Correct Answer - a,cd, | |
| 140. |
Which is (are) correct statement (s) ?A. Water is absorbed by anhydrous ` CaCl_2`B. Water is adsorbed by silica gelC. ` NH_3` is absorbed by water but adsorbed by charcoalD. Decolorisation of sugar by animal charcoal is based on adsorption |
| Answer» Correct Answer - a,b,c,d, | |
| 141. |
Which of the following is (are) colloid (s) ?A. Muddy watseB. MilkC. BloodD. Cholorophyll |
| Answer» Correct Answer - a,bc | |
| 142. |
The coagulation of sol particles may be brought in by :A. heatingB. adding oppositively charged solC. adding electrolyteD. persitent dialysis |
| Answer» Correct Answer - a,b,c,d, | |
| 143. |
Cationic surfacant (s) is `(rarr)` :A. the substances whose cation possesses surface activityB. ` C_n H_(2n+1) (OCH_2CH_2)_x OX`C. `C_(18) H_(37) NHCl`D. . |
| Answer» Correct Answer - a,c | |
| 144. |
According to Freundilich assorption isotherm , which of the following is correct ?A. ` x/m prop p^1`B. `x/m prop p^(1//n)`C. `x/m prop P^0`D. All the above are correct for different ranges of rpessure . |
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Answer» Correct Answer - d According to Freundilich adsorpton isorthem ` x/m = kp^(1//n)` ltbtgt ` 1//n` can have values between (0) to (1) over different ranges of pressure . |
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| 145. |
Difference in between crystallid and colloid is of :A. particle sizeB. to exhibit Tyndall effectC. diffusion through a membraneD. none of these |
| Answer» Correct Answer - a,b,c,d, | |
| 146. |
Assertion :- Amount of charge on hydrophobic sol is greater than hydrophilic sol. Reason :- Lyophobic sol is inorganic substance lycophilic sol is organic substance.A. If both Assertion & Reason are True & the Reason is a correct explanation of the Assertion.B. If both Assertion & Reason are True but Reason is not a correct explanation of the Assertion.C. If Assertion is True but the Reason is False.D. If both Assertion & Reason are False. |
| Answer» Correct Answer - B | |
| 147. |
Surfactants are the substances which show surface activity .Detergents possess surface activtiy as wll as detergency . Soaps are anionic class of detergents . It is the hydorphilic part of detergent momencule which possesses the tendecy to attract water moleculse wheras hydrophilic blances part orients away from waer . The hydrophilic-lipphilic balance (HLB) leads to affergation of anooic or non-ionic or cationci part of detergent to form icellse . Each molecule has the defintie concentration at defintie temperature at which it states to aggrater . It is due to teh presence of two moities in their molecules, surffactants stabilize emulision ( a water -oil system ) . Due to larger surface area, the mediacines are more effective in emulion form . Emulisons are ` w//o or o //w type`. A water soluble dye imparts its collour to ` o//w` emulsions. Which is incorrect about soaps?A. Soaps are metal salts of fatty acidsB. Soaps are anionic class of surfactants of detergentsC. Soaps form anionic micelles i.e., carrying -ve charge .D. none of these |
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Answer» Correct Answer - d ` RCOOON ararr RCOO^- + Na^+` Undergoes micelle formation to produce ` -ve` micelle . |
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| 148. |
Which of the following statement is wrong for lyophobic solA. Dispersed phase is generally in organic materialB. Can be easily coagulated by small addition of electrolyteC. Dispersed phase particles are poorly hydrated and colloid is stabilised due to charge on thhe colloidal particleD. Reversible in nature that is after coagulation can be easily set into colloidal form |
| Answer» Correct Answer - D | |
| 149. |
Which of the following substance gives a positively charged sol?A. GoldB. A metal sulphiteC. Ferric hydroxideD. An acidic dye |
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Answer» Correct Answer - C `Fe(OH)_(3)` Gives a positively charged sol as it adsorbs `Fe^(3+)` ions from `FeCl_(3)` solution. |
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| 150. |
Assertion: The property of adsorption is shown by solids to a much larger extent than liquids. Reason: Solids, particularly when finely divided, have a large surface area.A. Statement-1 is True, Statement-2 is True, Statement-2 is a correct explanation for Statement-1.B. Statement-1 is True, Statement-2 is True, Statement-2 is NOT a correct explanation for Statement-1.C. Statement-1 isTrue, Statement-2 is False.D. Statement-1 is False, Statement-2 is True. |
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Answer» Correct Answer - B |
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