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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.
| 151. |
Which of the following statements is more correct ?A. Catalyst only accelerates the rate of a chemical reactionB. A catalyst can retard the rate of a chemical reactionC. A catalyst can control the speed of a reactionD. A catalyst alters the speed of a reaction |
| Answer» Correct Answer - D | |
| 152. |
Which of the following statement is not true for a lyophobic solA. it can be easily solvatedB. It carries chargeC. The coagulation of this sol is irreversible in natureD. It is less stable in a solvent |
| Answer» Correct Answer - A | |
| 153. |
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 of the following forms a cationic miclels ?A. Sodium doecyl sulphate in waterB. Sodium dodecyl bezene sulphonate in waterC. Sodium octanoateD. Dodecyl ammonium chaoride |
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Answer» Correct Answer - d `(C_(12) H_(25)) NH_3Cl rarr c_(12) H_(24) NH_3^+ +Cl^-` Undrgoes micells formation to produce + ve micelle. |
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| 154. |
A colloid always :A. Contains two phasesB. Is a true solutionC. Contains three phasesD. Contains only water soluble particles |
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Answer» Correct Answer - A Colloid is hetergeneous, biphasic solution. |
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| 155. |
The extent of adsorption of a gas on a solid depends on :A. The nature of gasB. Pressure of gasC. Temperature of the systemD. All |
| Answer» Correct Answer - D | |
| 156. |
Which one of the following substance gives a positively charged sol?A. goldB. A metal sulphideC. ferric hydroxideD. An acidic dye |
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Answer» Correct Answer - C In `FeCl_(3)` is added to excess of hot water positively charged sol ferreic hydroxide is formed due to adsorption of `Fe^(+3)` ions. `Fe(OH)_(3)//Fe^(+3)` Positively charged sol. |
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| 157. |
What is sorption. |
| Answer» In some cases, both adsorption and absorption of substances takes place. This phenomenon is known as sorption. | |
| 158. |
Which one of the following is not a correct statementA. Physical adsorption is reversible in natureB. Physical adsorption involves vander waals forcesC. Rate of physical adsorption increases with increase of pressure on the adsorbateD. High active energy is involved |
| Answer» Correct Answer - D | |
| 159. |
The detergency action of soap is due to its :A. Emuilsification propertiesB. HydrolysisC. IonizationD. High molecular weight |
| Answer» Correct Answer - A | |
| 160. |
Which of the following kinds of catalysis can be explained by the adsorption theory?A. Homogenous catalysisB. Acid base catalysisC. Geterogenous catalysisD. Enzyme catalysis |
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Answer» Correct Answer - C Heterogeneous catalysis can be explaned by the adsorption theory. |
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| 161. |
colloidal solution of arsenious sulphide is coagulated byA. addition of electrolyteB. addition of non-electrolyteC. addition of solid `As_(2)S_(3)`D. None of these |
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Answer» Correct Answer - A `As_(2)S_(3)` is coagulated by addition of electrolyte due to opposite charge. |
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| 162. |
A colloidal solution of arsenious sulphide is most readily coagulated by the addition of a normal solution ?A. `NaCl`B. `CaCl_(2)`C. `Na_(3)PO_(4)`D. `Al_(2)(SO_(4))_(3)` |
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Answer» Correct Answer - D Arsenious sulphide is negatively charged sol so more the charge on cation of electrolyte, more the efficiency of electrolyte for coagulation. |
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| 163. |
colloidal solution of arsenious sulphide is coagulated byA. Addition of electrolyteB. Addition of non-electrolyteC. Addition fo solid `As_(2)S_(3)`D. None of these |
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Answer» Correct Answer - A `As_(2)S_(3)` is coagulated by addition of electrolyte due to opposite charge. |
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| 164. |
Sorption is the term used when :A. Adsorption takes placeB. Absorption takes placeC. Both take placeD. Desorption takes place |
| Answer» Correct Answer - C | |
| 165. |
Which of the following is not a characteristic of chemi-sorption :-A. Adsorption is irreversibleB. `Delta H` is of the order of 40 KJC. Adsorption is specificD. Adsorption increases with increase of surface area |
| Answer» Correct Answer - B | |
| 166. |
The rate od chemi-sorption :-A. Decreases with increase of pressureB. Is independent at high pressureC. Is maximum with increase of pressureD. Increases with increase of pressure |
| Answer» Correct Answer - B | |
| 167. |
Adsorption is a process in which a substance accumulates on the ……………… of the other substance.A. Accumulates on the phenomenon in which substanceB. Goes into the body of the other substanceC. Remains close to the other substnaceD. None is correct |
| Answer» Correct Answer - A | |
| 168. |
Give two differences between lyophilic and lyophobic colloids.A. Particle sizeB. Behaviour towards dispersion mediumC. FiltrabilityD. None of these |
| Answer» Correct Answer - B | |
| 169. |
Colloidal solution cannot be obtained from two such substances which areA. Insoluble in each otherB. In same physical stateC. In different physical stateD. None of these |
| Answer» Correct Answer - D | |
| 170. |
Which of the following methods is used for sol destruction?A. CondensationB. DialysisC. Diffusion through animal membraneD. Addition of an electrolyte |
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Answer» Correct Answer - D Traces of electrolytes are essential for stabilising the sols hence for sols destruction addition of electrolytes are required. |
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| 171. |
Which of the following condensation methods is used to prepare colloidal solution of arsenious sulphide?A. Double decompositionB. OxidationC. ReductionD. Hydrolysis |
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Answer» Correct Answer - A Lypophobic sols can be prepared by two types of methods: condensation methods and dispersion methods. In condensation methods, particles of atomic or molecular size are induced to combine to form aggregates having colloidal dimensions. For this purpose chemical as well as physical methods can be applied. In chemical methods, colloidal solutions are prepared by chemical reactions leading to formation of molecules by double decomposition (for compounds), oxidation (foro hydroxides). These molecules then aggregate leading to formation of sols: `As_(2)O_(3)+3H_(2)Soverset("Double decomposition")(rarr)As_(2)S_(2)(sol.)+3H_(2)O` `SO_(2)+2H_(2)Soverset("Oxidation")(rarr)3S(sol.)+2H_(2)O` . `2AuCl_(3)+3HCHO+3H_(2)Ooverset("reduction")(rarr)` `2Au(sol)+3HCOOH+6HCl` `FeCl_(3)+3H_(2)Ooverset("Hydrolyris")(rarr)Fe(OH)_(3)(sol.)+3HCl` |
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| 172. |
Among the electrolytes `Na_(2)SO_(4),CaCl_(2),As_(2)(SO_(4))_(3)` and `NH_(4)Cl,` the most effective coagulationf agent for `Sb_(2)S_(3)` negatively charged sol is :A. `Na_(2)SO_(4)`B. `CaCl_(2)`C. `Al_(2)(SO_(4))_(3)`D. `NH_(4)Cl.` |
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Answer» Correct Answer - C `Al^(3+)` ion has the maximum coagulating capacity. |
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| 173. |
What is sorption.A. Adsorption takes placeB. Adsorption takes placeC. Both take placeD. Desorption takes place |
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Answer» Correct Answer - C In sorption both adsorption and absorption take place. |
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| 174. |
There is desorption of physical adsorption whenA. Temperature is increasedB. Temperature is decreasedC. Pressure is increasedD. Concentration is increased |
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Answer» Correct Answer - A On increasing the temperature, adsorption decreases. |
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| 175. |
The emulsifying agent in milk isA. Lactic acidB. CaseinC. LactoseD. Fat |
| Answer» Correct Answer - B | |
| 176. |
What is an emulsifying agent ? |
| Answer» Emulsifying agent : The third substance which is added in small amounts to an emulsion to stabilize the emulsion is called emulsifying agent. | |
| 177. |
The method usually employed for the precipitation of a colloidal solution isA. dialysisB. condensationC. diffusion through animal membraneD. addition of electrolytes |
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Answer» Correct Answer - D The presence of small amount of appropriate electrolytes in necessary for the stability of the colloids. However, when an electrolyte is added in larger concentration, the particles of the sol take up the ions which are oppositely charged and thus get neutralised. The neutral particles then start aggregating given particles of larger size which are then precipitated. |
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| 178. |
the method usually employed for the destruction of a colloidal soloution charged sol ?A. `Cl^(-)`B. `SO_(4)^(2-)`C. `PO_(4)^(3-)`D. `[Fe(CN)_(6)]^(-4)` |
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Answer» Correct Answer - d |
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| 179. |
When a true solution is mixed with an excess of the other solvent in which the solute is insoluble but solvent is miscible, a ________ is obtainedA. lyophilic solB. hydrophobic solC. lyophobic solD. hydrophilic sol |
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Answer» Correct Answer - C This condensation method of preparation of lyophobic sol is called exchange of solvent (a physical method). For example, when a solution of sulphur in alcohol is poured in excess of water, a colloidal sol of sulphur is obtained. Another physical condensation method is excessive cooling. For example, the colloidal sol of ice in an organic solvent such as `CHCl_(3)` or ether can be obtained by freezing a solution of water in the solvent. The molecules of water which can no longer be held in solution separately combine to form particles of colloidal size. |
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| 180. |
Arrange the following electrolytes in the increasing order of coagulation power for the coagulation of `As_(2)S_(3)` sol : `K_(2)SO_(4) " " CaCl_(2)" " Na_(3)PO_(4) " " AlCl_(3)`A. `Ilt II lt IIIlt IV`B. `I=III lt II lt IV`C. `II lt IV lt I lt II`D. ` II lt III lt IV lt I` |
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Answer» Correct Answer - b |
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| 181. |
The method usually employed for the precipitation of a colloidal solution isA. dialysisB. addition of electrolytesC. diffusion through animal membraneD. condensation |
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Answer» Correct Answer - b |
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| 182. |
An emulsifying agent is a substance whichA. stabilies the emulsionB. de- stabilize the emulsionC. coagulates the emulsionD. break the interfacial film between suspended particle and medium |
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Answer» Correct Answer - a |
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| 183. |
In mechanical dispersion, the coarse suspension of the substance is brought into a colloidal state in the dispersion medium by grinding it in aA. colloid millB. ball millC. ultraviolet disintegratorD. all of these |
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Answer» Correct Answer - D Any of these could be used for mechanical dispersion which is one of the examples of dispersion method. In dispersion method, large particles of the substance are broken into particles of colloidal dimension in the pressure of dispersion medium. These are stabilized by adding some suitable stabilizer. The colloid mill consists of two metal discs, close together rotating at high speed (`7,000` revolutions per minute) in opposite directions. The suspension particles are torn off to the colloidal size. |
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| 184. |
Given below are a few electrolytes, indicate which one among them will bring about the coagulation of a gold sol quickest and in the least of concentration ?A. NaClB. `MgSO_(4)`C. `Al_(2)(SO_(4))_(3)`D. `K_(4)[Fe(CN)_(6)]` |
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Answer» Correct Answer - c |
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| 185. |
In the adsorption of oxalic acid on activated charcoal, the activated charcoal is calledA. AdsorbentB. AdsorbateC. AdsorberD. Absorber |
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Answer» Correct Answer - A According to definition of adsorbent. |
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| 186. |
Which property of colloids is not dependent on the change on colloidal particles?A. CoagulationB. ElectrophoresisC. ElectroosmosisD. Tyndall effect |
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Answer» Correct Answer - D Although a colloid appears to be homogeneous beayse the dispersed particals are quite small, it can be distinguished froma true solution by its ability to scatter light. The scattering of light by colloidal size paticles is known as Tyndall effect. For example, the atomsphere appears to be a clear gas, but a ray of sunshine gainst a dark background shows up many fine dust particles by light scattering. Coaulation is the process by which the dispersed phase of a colloid is made to aggregate and thereby separate from the continous phase. The curdling of milk when its sours is a typical example of coagulation. Milk is a colloidal suspension in which the particles are prevented from aggregating becayse they ahve elctrical chargs of the same sign. The ions responsible for the coagulation (curdling) are formed when lactose (milk dispersed phase in electrical field while electroosmosis is the movement of elctrically charged dispersion medium. |
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| 187. |
The formation of a colloidal from suspension isA. peptisationB. condenstionC. sedimentationD. fragmentation |
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Answer» Correct Answer - a |
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| 188. |
Addition of dil. Solution of `Ag NO_3 (aq)`, to excess of dil . Kl (aq). Gives :A. AglB. `+ve` sol of AglC. `-ve` sol of AglD. neutral sol of Agl |
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Answer» Correct Answer - C Sol particles of AgI adsorbs `I^-` (present in excess ) from solution . |
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| 189. |
The formation of a colloidal from suspension isA. peptisationB. condensationC. sedimentationD. fragmentation |
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Answer» Correct Answer - D Since particles of a suspension are bigger than colloidal particles, breaking down of a suspension into a colloid is called fragmentation. |
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| 190. |
Which of the following is the correct approximate value of ratio of size of colloidal particle to suspension ?A. Equal to 1.5B. Less than 1C. ZeroD. 10 Å |
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Answer» Correct Answer - B `("Size of colloidal particle")/("Size of suspension particle") = 10 - 10^(3) ("Å")/(gt 10^(3) "Å") = lt 1` |
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| 191. |
In a vessel `O_(2)` gas molecules were adsorbed on solid surface causing its partial pressure to decrease from 1 atm to 0.5 atm. Given : `N_(A) = 6 xx 10^(23)`, Volume of vessel = 2.24 L Temperature = 273 K, Total area of solid surface `= 10^(2) cm^(2)` Number of active sites per unit area `=10^(24) m^(-2)` Find number of `O_(2)` molecules adsorbed per active site. |
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Answer» Correct Answer - 3 |
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| 192. |
Which of the following electrolytes is most effective in the coagulation of gold solution?A. `NaNO_(3)`B. `K_(4)[Fe(CN)_(6)]`C. `Na_(3)PO_(4)`D. `MgCl_(2)` |
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Answer» Correct Answer - B `K_(4)[Fe(CN)_(6)]` is most effective in the coagulationof gold solution. |
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| 193. |
Identify the gas which is readily adsorbed by activated charcoal?A. `N_(2)`B. `SO_(2)`C. `H_(2)`D. `O_(2)` |
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Answer» Correct Answer - B Easily liquefiable gases like `SO_(2),NH_(3),CO_(2)` are adsorbed to a greater extent than the elemental gases like `N_(2),O_(2),H_(2)`. |
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| 194. |
Which property of colloids is not dependent on the charge on colloidal particles?A. Tyndall effectB. CoagulationC. ElectrophoresisD. electro-osmosis. |
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Answer» Correct Answer - A Tyndal effect is a optical property. Whereas other properties are electrical properties. Hence, dependent on the charge on colloids. |
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| 195. |
The property of colloidal suspension used to determine the nature of charge on the particles is :A. dialysisB. electrophoresisC. sedimentationD. ultrafiltration |
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Answer» Correct Answer - B Sol particles move towards oppositely charged elecrodes during the passage of current . |
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| 196. |
Which gas is adsorbed easily at solid surface?A. `SO_(2)`B. `H_(2)`C. `O_(2)`D. `N_(2)` |
| Answer» Correct Answer - A | |
| 197. |
Which adsorption takes place at low temperature?A. `DeltaH gt 0 and Delta S lt0`B. `DeltaHlt 0 and DeltaSlt0`C. `DeltaHgt0 and DeltaS gt0`D. `DeltaHlt0 and DeltaS gt 0` |
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Answer» Correct Answer - B During adsorption, there is always a decrease in residual forces of the surface i.e., there is decrease in surface energy which appears as heat. Adsorption, therefore, is invariable accompanied by evolution of heat i.e., it is an exothermic process, when a gas is adsorbed, the freedom of movement of **** molecules becomes restricted. this amounts to decrease in entropy of the gas after adsorption i.e, `DeltaS` is negative. Adsorptio is thus, accompanied by decrease in enthalpy as well decrease in entropy of the system. |
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| 198. |
Which property of colloidal solution is independent of charge on the colloidal particlesA. ElectrophoresisB. Electro-osmosisC. Tyndall effectD. coagulation |
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Answer» Correct Answer - C Tyndall effect is not depends on charge of colloidal particles. |
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| 199. |
which one of the following is not applicable to chemisorption ?A. it is slowB. it is irreversibleC. it is highly specificD. it is independent of temperature |
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Answer» Correct Answer - D Chemisorption first increases and then decreases with temperature. |
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| 200. |
Langmuir adsorption isotherm works particularly well :A. where multilayer adsorption ccan take placeB. where only unimolecular adsorption can take placeC. at initial stage where unimolecular adsorption takes place and not after that when multimolecular adsorption continuesD. in all of the above situations. |
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Answer» Correct Answer - B Since chemical bonds are formed between the particles of adsorbent and adsorbate, it is unimolecular thick layer only. |
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