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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.
| 1201. |
Which one of the following is lyophilic colloidA. GelatinB. SulphurC. goldD. Carbon |
| Answer» Correct Answer - A | |
| 1202. |
small liquid droplets dispersed in another liquid is called :A. suspenisonB. emulsionC. gelD. true solution |
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Answer» Correct Answer - b |
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| 1203. |
Which of the following is/are not true for lyophilic colloid ?A. These are prepared by special indirect methods.B. The particles must travel towards the anode or cathode under the influence of an electric field.C. These are called on intrinsic colloidD. Small quantity of electrolyte is sufficient to cause precipitation of these. |
| Answer» Correct Answer - A::B::D | |
| 1204. |
Which one of the following is correctly matched?A. Solid sol-cakeB. Aerosol-smokeC. Foam-mistD. Emulsion-curd |
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Answer» Correct Answer - B Smoke is an aerosol as it consists of solid carbon particles dispersed in air. |
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| 1205. |
which one of the following is lyophilic colloid ?A. PtB. GumC. FogD. Blood |
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Answer» Correct Answer - b |
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| 1206. |
which one of the sols acts as protetive colloid ?A. `As_(2)S_(3)`B. GelatinC. `Au`D. Fe`(OH)_(3)` |
| Answer» Correct Answer - B | |
| 1207. |
Methylene blue, from its aqueous solution is adsorbed on activated charcoal at `25^(@)C.`For this process, the correct statement isA. The adsorption requires activation at `25^(@)C`B. The adsorption is accompanied by a decreases in enthalpyC. Athe adsorption increases with increases of temperatureD. The adsorption is irreversible |
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Answer» Correct Answer - B As the adsorption of methylene blue over activated charcoal is physisorption it is accompanied by decrease in enthalpy. |
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| 1208. |
Among the following electrolytes, which is the most effective coagulation agent for `Sb_(2)S_(3)` solution?A. `Al_(2)(SO_(4))_(3)`B. `NH_(4)Cl`C. `CaCl_(2)`D. `Na_(2)SO_(4)` |
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Answer» Correct Answer - A Since `Sb_(2)S_(3)` is a negatively charged dol, `Al_(2)(SO_(4))_(3)` will be the most effective coagulant as its one formula unit can nullify six units of negative charge. According to Hardy-Schulze rule, order of effectiveness of cations is |
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| 1209. |
Assertion :- The graphical representation of physical adsorption with temp is Reason :- This is weak adsorption & adsorption is exothermic process.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 - A | |
| 1210. |
Tyndall effect is shown byA. colloidal solutionB. Osmotic solutionC. Isotonic solutionD. Hypertonic solution |
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Answer» Correct Answer - A only colloidal solution due to large of particles of colloids. |
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| 1211. |
which one of the sols acts as protetive colloid ?A. `As_(2)S_(3)`B. GelatinC. AuD. `Fe(OH)_(3)` |
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Answer» Correct Answer - b |
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| 1212. |
which one is an example of multimolecular coloid system?A. Aqueous starch solB. Aqueous enzyme solC. Alcoholic polystyene solD. Sulphur sol in water. |
| Answer» Sulphur sol is a multimolecular colloid. | |
| 1213. |
the electrical charge on a colloidal particle is indicated by :A. Brownian movementB. electrophoresisC. ultramicroscopeD. molecular sieves |
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Answer» Correct Answer - b |
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| 1214. |
Methylene blue, from its aqueous solution, is adsorbed on activated charcoal at `25^(@)C` . For process, the correct statement isA. The adsorption requires activation at `25^(@)C`B. The adsorption is accompanied by a decrease in enthalpyC. The adsorption increases with increase of temperatureD. The adsorption is irrvessible |
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Answer» Correct Answer - B Adsorption of methylene blue on activated charcoal is physical adsorption, hence it is reversible. Physical adsorption is exothermic `(DeltaH` is `-ve`)and its extent decreases with increases of temperature. |
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| 1215. |
Give one example each of multimolecular and macro-molecular colloids. |
| Answer» Correct Answer - Gold sol and sulphur sol. | |
| 1216. |
Assertion :- Physical adsorption forms multimolecular layer. Reason :- It contains covalent bond.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 - C | |
| 1217. |
Tyndall effect is shown byA. colloidal solution B. Osmotic solutionC. Isotonic solutionD. Hypertonic solution |
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Answer» Correct Answer - A only colloidal solution due to large of particles of colloids. |
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| 1218. |
Which is used in ending charge on colloidal solution?A. ElectronsB. ElectrolytesC. Positively charged solsD. Compounds |
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Answer» Correct Answer - B When excess of an electrolyte is added, the colloidal particles are precipitated because colloidal particles take up ions carrying charge opposite to that present on thermselves. This cause neutralization leading to their coagulation. |
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| 1219. |
which on e of the following is not used for perparing lyophilic sols ?A. starchB. GumC. GelatinD. Metal sulphide |
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Answer» Correct Answer - d |
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| 1220. |
which one is an example of multimolecular coloid system?A. soap disperseed in waterB. protein dispersed in waterC. Gold dispersed in waterD. gum dispersed in water |
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Answer» Correct Answer - C Example of multimolecular colloid system is a gold dispersed in water. |
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| 1221. |
If the dispersed phase is a liquid and the dispersion medium is a solid , the collide is known as `a//an`A. an emulsionB. a foamC. a soid solD. a solid emulsion |
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Answer» Correct Answer - D It is better called a gel. Examples are cheese, butter and jellies. However, if the dispersed is a liquid and the dispersion medium is also a liquied, it is called an emulsion. |
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| 1222. |
surface tension of lyophilic sols isA. lower than waterB. more than waterC. equal to waterD. none of these |
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Answer» Correct Answer - a |
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| 1223. |
The number of phases in colloidal system areA. oneB. twoC. threeD. four |
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Answer» Correct Answer - B Two phases in colloidal system (a) Dispersed phase (b) Dispersion medium. |
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| 1224. |
If the dispersed phase is a liquid and the dispersion medium is a solid , the collide is known as `a//an`A. solB. emulsionC. gelD. foam |
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Answer» Correct Answer - C `underset("Dispersed phase")(liqui d)+underset("Dispersed medium")(sol i d)=underset("Colloid")(Gel)(e .g But ter)`. |
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| 1225. |
the stability of lyophilic colloids is due toA. Charge on their particlesB. A layer of dispersion medium on their particlesC. The smaller size of their particlesD. The large size of their particles |
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Answer» Correct Answer - B Lyophilic possesses solvent loving nature and thus a thin layer of dispersed phases is formeed round sol particles. |
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| 1226. |
surface tension of lyophilic sols isA. Lower than that of `H_(2)O`B. More than that of `H_(2)O`C. Equal to that of `H_(2)O`D. none of these |
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Answer» Correct Answer - A Surface tension of lyophilic sol is lower than that of the dispersion medium. |
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| 1227. |
Collioidal sols can be purified byA. dialysisB. ultrafiltrationC. ultracentrationD. ultracentrifugation |
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Answer» Correct Answer - D (a) In dialysis , sol under purification is placed in a bag made of cellophane or parchment. This is suspended in water. Small molecules and ins pass through the membrane, but the sol is retained. When an elecrtric field is applied during dialysis, it is called electrodialysis. (b) Colloidal sols can also be purified by using special type of graded filters called ultra-filters and method is called ultra-filtration. these ultra-filter papers allows only the electrolytes to pass through under the influence of suction or pressure pump. (c ) in ultra-centrifugation method, colloidal sol is polaced in ultra-centrifuge. Under high speed, colloidal sols settle down at the bottom, while impurities remains in solution. |
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| 1228. |
the colloidal sols are purified byA. PeptisationB. CoagulationC. DialysisD. Flocculation |
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Answer» Correct Answer - C Dialysis is a process of removing impurites from colloidal sol. |
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| 1229. |
smoke is a dispersion ofA. gas in gasB. gas is solidC. solid in gasD. liquid in gas |
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Answer» Correct Answer - C Smoke is solid in gas dispersion. |
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| 1230. |
Smoke is a dispersion ofA. gas in gasB. gas in solidC. solid in gasD. liquid in gas |
| Answer» Correct Answer - C | |
| 1231. |
Which of the following is used to produce smoke screens?A. CalciumB. Zinc sulphideC. Sodium carbonateD. Zinc phosphate |
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Answer» Correct Answer - A Smoke screens are used in warfare for the purpose of concealment and camouflage. `Ca_(3)P_(2)+6H_(2)Orarr3Ca(OH)_(2)+2PH_(3)` Phosphine `(PH_(3))` so formed spontaneously catches fire to give `P_(2)O_(5)` `2PH_(3)+4O_(2)rarrP_(2)O_(5)+3H_(2)O` `P_(2)O_(5)` forms a white dense smoke screen. Very fine particles of titanium oxide dispersed in air are also used to create smoke screens. They are usually ejected from aeroplanes. As titanium oxide is very heavy, the smoke screen drops down rapidly as a curtain of dazzing whiteness. |
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| 1232. |
A catalyst :A. Increases the average kinetic energy of reacting moleculesB. Increases the activation energyC. Alters the reaction mechanismD. Increases the frequency of collisions of reacting species |
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Answer» Correct Answer - C Catalyst alters the reaction mechanism. |
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| 1233. |
The addition of a catallystic during a chemical reaction alters which of the following quantities ?A. EntropyB. Internal enegyC. EnthalpyD. Activation energy |
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Answer» Correct Answer - D The addition of catalyst during a chemical reaction alters the activation energy. |
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| 1234. |
Butter is a colloid formed when :A. Fat is dispersed in fatB. Fat is dispersed in waterC. Water is dispersed in fatD. Supension of casein in water |
| Answer» Correct Answer - C | |
| 1235. |
The Tyandall effect is observed only when following conditions are satisfied (a) The diameter of the dspersed particle is much smaller than the wavelength of the light used (b) The diameter of the dispersed particles isnot much smaller than the wavelength of the light uses (c ) The refractive indices of the dispersed phase and sispersion medium are almost similar in magnitude. (d) The refractive indices of the dispersed phase and the dispersion medium differ greatly in magnitude.A. A and CB. B and CC. A and DD. B and D |
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Answer» Correct Answer - D Conditions (B) and (D) must be satisfied. For details, consult section. 20 |
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| 1236. |
The charge on `As_(2)S_(3)` sol is due to:A. adsorption of `S^(-2)` ionsB. absorption of `S^(2-)` ionsC. absorption of `H^(+)` ionsD. adsorption of `H^(+)` ions |
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Answer» Correct Answer - A It is the correct statement. |
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| 1237. |
Which of the following is not favourable condition for physical adsorption ?A. High pressureB. Low temperatureC. High temperatureD. High critical temperature of adsorbate |
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Answer» Correct Answer - C Adsorption is an exothermic process. In case of physical adsorption, low temperature is favourable |
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| 1238. |
Which of the following is not a favourable condition for physical adsorption?A. High pressureB. Negative `DeltaH`C. Higher critical temperature of adsorbateD. High temperature |
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Answer» Correct Answer - D |
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| 1239. |
Which of the following is an example of absorption?A. Water on silica getB. Water on anhydrous calcium chlorideC. Hydrogen on finely divided nickelD. Oxygen on metal surface |
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Answer» Correct Answer - B Anhydrous `CaCl_(2)` absorbs water or moisture. |
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| 1240. |
In which of the following reactions heterogeneous catalysis is involved? (i) `2SO_(2)(g)+O_(2)(g) overset(NO(g))(to) 2SO_(3)(g)` (ii) `2SO_(2)(g) overset(Pt(s))(to) 2SO_(3)(g)` (iii) `N_(2)(g)+3H_(2)(g) overset(Fe(s))(to) 2NH_(3)(g)` (iv) `CH_(3)COOCH_(3)(l)+H_(2)O(l) overset(HCl(l))(to)CH_(3)COOH(aq)+CH_(3)OH(aq)`A. (ii), (iii)B. (ii), (iii) and (iv)C. (i), (ii) and (iii)D. (iv) |
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Answer» Correct Answer - C (i) Reaction in which catalyst is in different phase than other (reactants and products ) is known as heterogeneous catalysis. (ii) `2SO_(2)(g) overset(Pt(s))(to) 2SO_(3)(g)` Here, reactant `SO_(2)` and product `SO_(3)` are in gaseous phase while platinum is in solid phase. So, this reaction represents a heterogeneous catalysis. (iii) `N_(2)(g)+3H_(2)(g) overset(Fe(s))(to) 2NH_(3)(g)` Similarly, here `N_(2)` and `H_(2)` reactants are in gaseous phase while `NH_(3)` is in solid phase. Whereas in other reactions catalyst is in same phase with reactant(s) and product(s). |
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| 1241. |
On the basis of data below predict which of the following gases shows least adsorption on a definite amount of charcoal ? A. `CO_(2)`B. `SO_(2)`C. `CH_(4)`D. `H_(2)` |
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Answer» Correct Answer - D More easily liquefiable gases asre adsorbed readily. Thus, `H_(2)` gas having low critical temperature (33 K) is not easily liquified and shows least adsorption. |
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| 1242. |
Which of the following is an example of absorption?A. Water on silica gelB. Water on calcium chlorideC. Hydrogen on finely divided nickelD. Oxygen on metal surface |
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Answer» Correct Answer - B Absorption means penetration of adsorbate molecules into the bulk of the adsorbent e.g., water on calcium chloride. When water is spread over calcium chloride, water get penetrate into bulk of the calcium chloride. |
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| 1243. |
On the basis fo data given below predict which of the following gases shows least adsorption on a definite amount of charcoal? `{:("Gas" ,,CO_(2),,SO_(2),,CH_(4),,H_(2)),("Critical temp./K",,304,,630,,190,,33):}`A. `CO_(2)`B. `SO_(2)`C. `CH_(4)`D. `H_(2)` |
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Answer» Correct Answer - D Lesser the value of critical temperature of gasses lesser will be the extent of adsorption. Here `H_(2)` has lowest value of critical temperature, i.e., 33. Hence, hydrogen gas shows least adsorption on a definite amount of charcoal. |
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| 1244. |
Two compounds I and II are eluted by column chromatography (adsorption of `I gt II`). Which one of the following is a correct statement ?A. I movers faster and has higher `R_(f)` value than IIB. II moves faster and has higher `R_(f)` value than IC. I moves slower and has higher `R_(f)` value than IID. II moves slower and has higher `R_(f)` value than I |
| Answer» Correct Answer - B | |
| 1245. |
Movement of dispersion medium under the influence of electric field is known asA. electrodialysisB. electrophoresisC. ElectroosmosisD. cataphoresis |
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Answer» Correct Answer - C When movement of particles (electrophoresis) is prevented by some suitable means, it is observed that the dispersion medium begins to move in an electric field. This phenomenon is termed as electroosmosis. |
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| 1246. |
The charge on the colloidal particles does not account for the stability sols. |
| Answer» Correct Answer - F | |
| 1247. |
Which of the following is not an explanation for the origin of charge on the colloidal particles ?A. Due to frictional electrificationB. Due to dissociation of surface moleculesC. Due to electrophoresisD. Due to selective adsorption of ions |
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Answer» Correct Answer - C Due to the presence of charge on colloidal particles, electrophoresis takes place. |
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| 1248. |
The combination of two layers of opposite charges aroung the colloidal particle is called Helmholtz electrical double layer. The potential difference between the fixed layer and the diffused layer of opposite charge is calledA. electrode potentialB. zeta potentialC. adsorption potentialD. diffused potential |
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Answer» Correct Answer - B The first layer of ions is firmly held and is termed as fixed layer while the second layer is mobile or diffused layer according to Helmholtz electrical double layer. The potential difference between fixed and diffused layer is called electrokinetic potential or zeta potential. |
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| 1249. |
If `Fe_(OH)_(3)` sol is subjected to electrophoresis then which of the following statements regarding coagulation will be correct?A. No coagulation will occur at any electrodeB. coagulation will occur at cathodeC. Coagulation will occur at anodeD. Coagulation will occur at both the electrodes |
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Answer» Correct Answer - B |
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| 1250. |
Give four examples of heterogeneous catalytic reactions. |
| Answer» In heterogeneous catalysis, the catalyst is present in a different phase than that of the reactants, e.g., | |