InterviewSolution
Saved Bookmarks
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.
| 1351. |
Why do we add alum to purify water ? |
| Answer» We add alum to purify water as alum coagulates the colloidal impurities present in water, so that these impurities get settle down and remove by decantation or filtration. Thus, water gets purified by adding alum to water. | |
| 1352. |
Alum purifies muddy water byA. dialysisB. absorptionC. coagulationD. ultrafiltration |
|
Answer» Correct Answer - c |
|
| 1353. |
The incorrect statement about physical adsorption isA. it lacks specificityB. it is generally reversibleC. porous surfaces are good adsorbentD. heat of adsorption is quite high. |
|
Answer» Correct Answer - D Heat of adsorption of physical adsorption is quite low. |
|
| 1354. |
Ultra-centrifugation used to purify colloidal solution is based on the difference ofA. electrical changeB. densityC. sizeD. all of these |
|
Answer» Correct Answer - B In this method, the colloidal sol is taken in a tube which is placed in an ultra-centrifuge. On rotation of the tube at high speeds, the colloidal particles being more dense settle down at the bottom of the tube and the impurities remain in the solution called centrifuge. The settled colloidal particles are mixed with an appropriate dispersing medium to regenerate the sol. |
|
| 1355. |
Emulsions are normally prepared by shaking the two components together vigorously although some kind of emulsifiying agent usually has to added to stabilize the product. This emulsifying agent amy be a soap or other sufactant (surface active) sepcies or a lyophilic sol that forms a protective film around the dispersed phase. Emulsion broadly classified into two types: (i) Oil in water emulsions (O/W): Oil acts as dispersed phase and water acts as dispersion medium. (ii). Water in oil emulsion (W/O): Water acts as dispersed phase and oil acts as dispersion medium Due test, dilution test may be emplyoyed for identification of emulsions. Q. Read two statment s: (1) milk is an example of oil in water (O/w) type emulsion (2) cold cream is an example of water in oil (W/O) type emulsionA. only statement 1 is correctB. only statement 2 is correctC. both are correctD. none of these |
|
Answer» Correct Answer - c |
|
| 1356. |
Which of the following techniques are applied for demulsi-fication?A. FreezingB. BoilingC. CentrifugationD. All of these |
|
Answer» Correct Answer - D The separation of an emulsion into its constitutent liquids is called demulsification. Emulsions can be broken into consistutent liquids by heating, freezing centrifugation, electrostatic precipitation or chemical methods which destroy the emulsifying agents. |
|
| 1357. |
Which of the following substances will precipitate the negatively charged emulsions ?A. KClB. GlucoseC. UreaD. NaCl |
|
Answer» Correct Answer - A::D both KCl and NaCl will provide positive `(K^(+), Na^(+))` for the precipitation of negatively charged emulsions. |
|
| 1358. |
Assertion: A quious gold colloidal solution is red in colour. Reason: The colour arises due to scattering of light by colloidal gold particles.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 and the reason is not the correct explanation of the assertion.C. If assertion is true but reason is false.D. If assertion is false but reason is true. |
|
Answer» Correct Answer - A The colour is due to scattering. It depends upon the size of particles. Finest gold sol has red colour. As the size of the particle increase, it becomes purple , then blue and finally golden yellow. |
|
| 1359. |
Which is correct in case of van der Waals adsorption?A. High temperature, low pressureB. High temperature ,high pressureC. Low temperature , low pressureD. Low temperature , high pressure |
|
Answer» Correct Answer - D van der Waals adsorption i.e. physisorption increases at low temperature and high pressure. |
|
| 1360. |
Assertion : Aqueous gold colloidal sol is red in colour. Reason : The colour arised due to scattering of hight by particles of gold.A. If both assertion and reason are correct and reason is correct explanation for assertion.B. If both assertion and reason are correct but reason is not correct explanation for assertion.C. If assertion is correct but reason is incorrect.D. If assertion and reason both are incorrect. |
|
Answer» Correct Answer - A Reason is the correct explanation for assertion. |
|
| 1361. |
Assertion(A): `Fe^(3+)` can be used for coagulation of `As_(2)S_(3)` sol. Reason (R): `Fe^(3+)` reacts with `As_(2)S_(3)` to give `Fe_(2)S_(3.)`A. If both (A) and (R) are correct, and (R) is the correct explanation of (A)B. If both (A) and (R) are correct, but (R) is the correct explanation of (A).C. If (A) is correct, but (R) is incorrect.D. If (A) is incorrect, but (R) is correct. S |
|
Answer» Correct Answer - C `Fe^(3+)` neutralizes the charge on the negatively charged `As_(2)S_(3)` particles. |
|
| 1362. |
Alum is used to purify water obtained from natural sources. Explain. |
| Answer» The water obtained from natural sources often contains suspended impurities. Alum is added to such water to coagulate the suspended impurities and make water fit for drinking purposes. | |
| 1363. |
Which property is observed in an emulsion?A. Tyndall effectB. Brownian motionC. Both (1) & (2)D. None of these |
| Answer» Correct Answer - C | |
| 1364. |
O/W type emulsion meansA. Oxygen dispersed in waterB. Water dispersed in oxygenC. Oil dispersed in waterD. Water dispersed in oil |
| Answer» Correct Answer - C | |
| 1365. |
An emulsion is a colloidal solution consisting of :A. SolidB. LiquidC. GasD. Medium |
| Answer» Correct Answer - B | |
| 1366. |
Emulsion can be detroyed by :A. the addition of an emulsifierB. electrophoresis with a high potentialC. freezingD. all of these |
|
Answer» Correct Answer - b,c |
|
| 1367. |
Which of the following is not correct about emulsions?A. The droplets in emulsions are often positively charged.B. They can be precipitated by electrolytesC. They show Brownian movementD. They show Tyndall effect |
|
Answer» Correct Answer - A The droplets in emulsions are often negatively charged. |
|
| 1368. |
Assertion : Physical adsorption increases with increase in temperature. Reason : Physical adsorption is an endothermic process.A. If both assertion and reason are true and reason is the correct explanation of assertion.B. If both assertion and reason are true but reason is not the correct explanation of assertionC. If assertion is true but reason is falseD. if both assertion and reason are false |
|
Answer» Correct Answer - D Physical adsorption is an exothermic process. Solid + Gas `hArr` Gas/Solid + Heat So according to Le-Chatelier principle it will decrease with increasing temperature. |
|
| 1369. |
Assertion : Hydrolysis of ester is an example of auto-catalytic reaction. Reason : A catalyst speeds up the process without participating in the mechanism.A. If both assertion and reason are true and reason is the correct explanation of assertion.B. If both assertion and reason are true but reason is not the correct explanation of assertionC. If assertion is true but reason is falseD. if both assertion and reason are false |
|
Answer» Correct Answer - C A catalyst participates in the mechanism of the reaction and is regenerated after the reaction. |
|
| 1370. |
Assertion(A): Aqueous gold colloidal solution is red in colour. Reason(R): The colour arises due to scattering of light by colloidal gold particles.A. If both (A) and (R) are correct, and (R) is the correct explanation of (A)B. If both (A) and (R) are correct, but (R) is the correct explanation of (A).C. If (A) is correct, but (R) is incorrect.D. If (A) is incorrect, but (R) is correct. S |
|
Answer» Correct Answer - A The colours is due to scattering. It depends upon the size of particles. Finest gold sol has red colour. As the size of the particles increases, it becomes purple, then blue, and finally golden yellow. |
|
| 1371. |
Why medicines are more effective in colloidal state ? |
| Answer» Colloidal medicines are more effective because they have large surface area and are therefore easily assimilated. | |
| 1372. |
Assertion(A): Langmuir adsorption is a single-layer phenomenon. Reason(R): It is due to van der Waals forces.A. If both (A) and (R) are correct, and (R) is the correct explanation of (A)B. If both (A) and (R) are correct, but (R) is the correct explanation of (A).C. If (A) is correct, but (R) is incorrect.D. If (A) is incorrect, but (R) is correct. |
|
Answer» Correct Answer - C The single layer fromed may be due to van der Waals adsorption or chemisorption. |
|
| 1373. |
Why are some medicines more effective in the colloidal form ?A. the charged colloidal particles present in itB. the large surface area and easy assimilationC. precipitation of medicine in the bloodD. the stabilisation of medicine in colloidal form. |
|
Answer» Correct Answer - B Medicines are more effectives in the colloidal form because of large surface area and are easily assimilated in this form. |
|
| 1374. |
The type of emulsion formed depends uponA. the relative amounts of the two liquidsB. nature of the emulsifying agentC. both of theseD. none of these |
|
Answer» Correct Answer - C If water is in excess, it is oill-in-water emulsion. If, on the other hand, oil is in excess, it is water-in-oil emulsion. Emulsions can be diluted with any amount of the dispersion medium. On the other hand, the dispersed liquid when mixed, forms a separate layer. The presence of soluble soaps as the emulsifying agent generally favours the formation of emulsion of oil-in-water type, whereas the presence of insolube soaps (containing non-alkali metal atoms) favour the formation of emulsions of water-in-oil type. |
|
| 1375. |
Assertion(A): The micelle formed by sodiumm stearate in water has -COO groups at the surface. Reason(R): Surface tension of water is reduced by addition of stearate.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 and the reason is not the correct explanation of the assertion.C. If assertion is true but reason is false.D. If assertion is false but reason is true. |
|
Answer» Correct Answer - B Here both assertion and reason are correct but reason is not a correct explanation of asssertion. Micelle is formed if molecules with polar and nonpopular ends assemble in bulk to give nonpolar interior and polar exterior. |
|
| 1376. |
Assertion : Physisorption of a gas adsorbed at low temperature may change into chemisorption at a high temperature. Reason : Usually low pressure is also favourable for chemisorptionA. If both assertion and reason are true and reason is the correct explanation of assertion.B. If both assertion and reason are true but reason is not the correct explanation of assertionC. If assertion is true but reason is falseD. if both assertion and reason are false |
|
Answer» Correct Answer - C Usually high pressure is also favourable for chemisorption . |
|
| 1377. |
Assertion(A): The micelle formed by sodiumm stearate in water has -COO groups at the surface. Reason(R): Surface tension of water is reduced by addition of stearate.A. If both (A) and (R) are correct, and (R) is the correct explanation of (A)B. If both (A) and (R) are correct, but (R) is the correct explanation of (A).C. If (A) is correct, but (R) is incorrect.D. If (A) is incorrect, but (R) is correct. S |
| Answer» Correct Answer - A | |
| 1378. |
Assertion(A): Physical adsorption of milecules on the surface requires activation energy. Reason(R): Because the bonds of adsorbed molecules are broken.A. If both (A) and (R) are correct, and (R) is the correct explanation of (A)B. If both (A) and (R) are correct, but (R) is the correct explanation of (A).C. If (A) is correct, but (R) is incorrect.D. If (A) is incorrect, but (R) is correct. S |
| Answer» Activation energy is needed for chemical adsorption and not for physical adsorption. Breaking of bonds also takes place only in chemical adsorption. | |
| 1379. |
Assertion(A): Physical adsorption of molecules on the surface requires activation energy. Reason(R): Because the bonds of adsorbed molecules are broken.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 - D | |
| 1380. |
Assertion : The concentration of sulphide ore by froth floatation process is based on emulsification. Reason : The addition of pine oil in w ater froms an emulsion.A. If both assertion and reason are correct and reason is correct explanation for assertion.B. If both assertion and reason are correct but reason is not correct explanation for assertion.C. If assertion is correct but reason is incorrect.D. If assertion and reason both are incorrect. |
|
Answer» Correct Answer - A Reason is the correct explanation for assertion. |
|
| 1381. |
Assertion: Medicines in the colloidal state are more effective. Reason: In the colloidal state, the medicine are easily assimilated by the body.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 and the reason is not the correct explanation of the assertion.C. If assertion is true but reason is false.D. If assertion is false but reason is true. |
|
Answer» Correct Answer - A Medicine are easily accepted by body becaue of larger size of colloidal medicines. |
|
| 1382. |
The principal emulsifying agents for `"O"//W` emulsions are pro (i) proteins , (ii) gums (iii) natural soaps , (iv) synthetic soapsA. (iii), (iv)B. (ii), (iii), (iv)C. (i), (ii), (iii), (iv)D. (i), (ii), (iii) |
|
Answer» Correct Answer - C The process of making an emulsion is known as emulsification. Emulsion may be obtained by vigorously mixing both the liquids. However, this gives an unstable emulsion. The dispersed drops at once come together and form separate layers. To stabilize an emulsion, the addition of a small quantity of a third substance known as emulsifiying agent or emulsifier is essential. Soaps and detergents are most frequntly used as emulsifirers. They coat the drops of an emulsion and check them from coming together and the emulsion is thus stabilized. The principle emulsifying agents for `"O"//W` emulsion (i.e. oil dispersed in water) are proteins, gums, agar, natural and synthetic soaps while the principle emulsifying agents for `W//"O"` emulsions (i.e. water dispersed in oil) are heavy metal salts of fatty acids, long chain alcohols, lampblack etc. |
|
| 1383. |
The dispersed phase in colloidal iron (III) hydroxide and collodial gold is positively and negtively charged respectively with of the following statement is not correct ?A. Coagulation in both sols can be brought about by electrophoresisB. Mixing the sols has no effectC. Sodium sulphate solution causes coagulation in both solsD. Magnesium chloride solution coagulates, the gold sol more readily than the iron (III) hydroxide sol. |
| Answer» Correct Answer - B | |
| 1384. |
Assertion(A): The micelle formed by sodiumm stearate in water has -COO groups at the surface. Reason(R): Surface tension of water is reduced by addition of stearate.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 | |
| 1385. |
Assertion: Colloidal solution exhibit Tyndall effect while true solution particles. Reason: Because the size of the colloidal particles is large enough to scatter light as compared to size of the true solution particles.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 and the reason is not the correct explanation of the assertion.C. If assertion is true but reason is false.D. If assertion is false but reason is true. |
|
Answer» Correct Answer - A Size of colloidal particle is sufficient to scatter light and true solution particle size is smaller. |
|
| 1386. |
Assertion: Physisorption of molecules occures on surface only. Reason: in this process, the bonds of the adsorbed molecules are broken.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 and the reason is not the correct explanation of the assertion.C. If assertion is true but reason is false.D. If assertion is false but reason is true. |
|
Answer» Correct Answer - C Van der Waals bond is formed between adsorbate and adsorbent during physical adsorption. |
|
| 1387. |
Which of the following is an example of oil in water emulsion?A. Cod liver oilB. ButterC. Cold creamD. Vanishing cream |
|
Answer» Correct Answer - D Emulsions can be broadly classified into two types: (i) Oil in water emulsion (O/W type): In this type of emulsion, oil acts as dispersed phase and water acts as dispersion medium. Some examples of this type of emulsion are milk, vanishing cream, etc. In milk, liquid fat is dispersed in water. (ii) Water in oil emulsion (W/O type): In this type of emulsion, water acts as dispersed phase and oil (orangic solvent) acts as dispersion medium.Common examples of this type are butter, cold cream and cod liver oil. Cod liver oil is the oil expressed from the fresh liver of the cod, Gadus callarias. It is a pale yellow liquid, slightly soluble source of `A` and `D` vitamins and other food factors and is used in the prevention and cure of rickets in growing childern. The following tests may be employed to distinguish between the two types of emulsion: (i) Dye test: Some oil soluble dye is added to the emulsion, if the background becomes coloured, the emulsion is water-in-oil type. (ii) Dilution test: If the emulsion can be diluted with water, this indicates that water is the dispersion medium and the emulsion is of oil-in-water type. In case the added water forms a separate layer, the emulsion is water-in-oil type. |
|
| 1388. |
Statements : The concentration of sulphide ores by froth floation is based on emulsifcation . Expabnations : Pine oil in water forms emulsion .A. S is correct but E is wrong .B. S is worong but E is correctC. Both S and E are correct and E is correct explanation of (S) .D. Both S and E are correct but E is not correct explanation of S. |
|
Answer» Correct Answer - C Both are different facts but treue. |
|
| 1389. |
Assertion: Alcohols are dehydrated to hydrocarbons in the presence of acidic zeolites. Reason: Zeolites are pourous catalysts.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 | |
| 1390. |
Assertion: Alcohols are dehydrated to hydrocarbons in the presence of acidic zeolites. Reason: Zeolites are pourous catalysts.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 and the reason is not the correct explanation of the assertion.C. If assertion is true but reason is false.D. If assertion is false but reason is true. |
|
Answer» Correct Answer - B Both assertion and reason are correct but dehydration is not due to porous nature but due to the acidic group present in zeolites. |
|
| 1391. |
which of the following statement is not true about the oil - in - water type emulsion ?A. Addition of small amount of water , no separate layer of water is formedB. Addition of a small amount of oil soluble dye renders the entire emulsion colouredC. Addition of oil results in the formation of two layersD. Addition of a small amount of an electroyte increases the conductivity of the emulsion |
|
Answer» Correct Answer - b |
|
| 1392. |
A freshly prepared `Fe(OH)_(3)` precipitate is peptized by adding `FeCl_(3)` solution. The charge on the colloidal particle is due to preferential adsorption ofA. `Cl^(-)` ionsB. `Fe^(+++)` ionsC. `OH^(-)` ionsD. None |
| Answer» Correct Answer - B | |
| 1393. |
A freshly formed ppt of `SnO_(2)` is peptized by a small amount of `NaOH` . These colloidal particles may be represented asA. `[SnOH_(2)]SnO_(3)^(2-),2Na^(o+)`B. `[SnOH_(2)]Sn^(4+),O^(2-)`C. `[SnOH_(2)]Na^(o+),OH^(Θ)`D. `[SnO_(2)]Sn^(4+),OH^(Θ)` |
| Answer» Correct Answer - A | |
| 1394. |
A reddish brown positively charged sol is obtained by adding small quantity of `FeCl_(3)` solution to freshly prepared and well washed `Fe(OH)_(3)` precipitate. How does it take place ? |
|
Answer» It is due to adsorptions of `Fe^(3+)` ions on the surface of `Fe(OH)_(3)` which gives colloidal sol. `Fe(OH)_(3) (ppt.) + Fe^(3+)` (ions adsorbed) `to [Fe(OH)_(3)]Fe^(3+)` (colloidal sol). |
|
| 1395. |
select incorrect statement :A. gold sol is multimolecular colloidB. large number of particles of a substance aggregate together and formed multimolecular colloidsC. Metal sulphides are lyophobic colloidsD. sulphur sol is multimolecular colloid oand hydrophilic in nature |
|
Answer» Correct Answer - d |
|
| 1396. |
Under the influemce of an electric field, the particles in a sol migrate towards cathode. The coagulation of the same sol is studied using `NaCl,Na_(2)SO_(4)` , and `Na_(3)PO_(4)` solutions. Their coagulation values will in the order a. `NaClgtNa_(2)SO_(4)gtNa_(3)PO_(4)` b. `Na_(2)SO_(4)gtNa_(3)PO_(4)gtNaCl` c. `Na_(3)PO_(4)gtNa_(2)SO_(4)gtNaCl` d. `Na_(2)SO_(4)gtNaClgtNa_(3)PO_(4)`A. NaClB. `Na_(2) So_(4)`C. `Na_(3) PO_(3)`D. same for all |
|
Answer» Correct Answer - a |
|
| 1397. |
A freshly prepared `Fe(OH)_(3)` precipitate is peptized by adding `FeCl_(3)` solution. The charge on the colloidal particle is due to preferential adsorption ofA. `Cl^(-)` ionsB. `fe^(3+)` ionsC. `OH^(-)` ionsD. none of these |
|
Answer» Correct Answer - b |
|
| 1398. |
select incorrect statement:A. Micelles are associated collodiesB. the electrical charge on a colloid paritcle is indicated by electrophoresisC. formation of micelles takes place above Kraft temperatureD. formation of micells takes place below CMC. |
|
Answer» Correct Answer - d |
|
| 1399. |
Bredigs arc method involves :A. dispersion of metalB. condenstion of metalC. disoersion as well as condenstionD. neither dispersion nor condensation |
|
Answer» Correct Answer - c |
|
| 1400. |
In the adsorption of a gas on soild, Freundlich isotherm is obeyed . The slope of the plot is zero. Thus, the extent of adsorption isA. directly proprotional to the pressure of gasB. inversely proprotional to the pressure of the gas.C. independent of the pressure of the gas.D. proportional to the square of the pressure of the gas. |
|
Answer» Correct Answer - C `x/m = kp^(1//n)` In `x/m = 1nK + 1/n 1n p" "[because "Slope" =1/n=0]` Thus, `x/m=kp^(0) implies x/m =k` |
|