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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.
| 951. |
What are optimum temperature and pH for the enzymes to act best ? |
| Answer» Correct Answer - pHrange 5-7 and temperature range 298- 310 k. | |
| 952. |
Which of the following statements about the zeolites is false?A. They are used as cation exchangersB. They have open structures which enables them to take up small moleculesC. They are aluminosilicates having three dimensional networkD. In zeolites some of rthe `SiO_(4)^(4-)` anions are replaced by `AlO_(4)^(5-)` and `AlO_(6)^(9-)` ions. |
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Answer» Correct Answer - D Only tetrahedral `AlO_(4)^(5-)` ions which have nearly the same size as the tetrahedral `SiO_(4)^(4-)` anions can replace the latter to from zeolites, provided electerical neutrality is maintained. |
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| 953. |
According to the adsorption theory of catalysis the speed of the reaction increases becauseA. adsorption lowers the activetion energy of the reactionB. the concentration of reaction molecules at the active centres of the catalyst becomes high due to adsorptionC. in the process of adsorption, the activation energy of the molecules becomes largeD. adsorption produces heat which nincrease the speed of the reaction |
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Answer» Correct Answer - A In surface catalysis or heterogeneous catalysis, the reaction becomes fast on account of lowering of activation energy. The old view point was that the increased concentration of the reactants on the surface influences the rate of reaction. |
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| 954. |
Buffer is a colloidal solution of:-A. solid-solidB. liquid-solidC. solid-liquidD. gas-solid |
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Answer» Correct Answer - B In buffer the dispersed phase is liquid, while dispersion mediu is solid it is a gel. It is liquid-slid-colloid. |
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| 955. |
Which one of the following is not a colloidal solution:-A. SmokeB. InkC. AirD. Blood |
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Answer» Correct Answer - C Air is not a colloidal solution because it is a homogenous mixture. |
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| 956. |
Milk can be preserved by adding a few drops of:-A. Formic acid solutionB. Formaldehyde solutionC. Acetic acid solutionD. Acetaldehyde solution |
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Answer» Correct Answer - B Milk can be preserved by adding a few drops of HCHO solution. HCHO is an emulsifier. |
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| 957. |
Which of the following substances is not used for preparing lyophilic solsA. StarchB. gumC. gelatinD. Metal sulphide |
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Answer» Correct Answer - D Metal sulphide is not sued for preparing lyophilic sol. |
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| 958. |
Which of the following is not an emulsionA. ButterB. Ice creamC. MilkD. Cloud |
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Answer» Correct Answer - D It is liquid in gas colloidal solution. |
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| 959. |
What is adsorption ? Discuss the mechanism of adsorption of gases on solids. |
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Answer» Adsorption : The accumulation (or) concentration of a substance on the surface rather than in the bulk of solid (or) liquid is known as adsorption. Eg : Adsorption of gases like `O_(2), H_(2), C_(12)` etc., on charcoal. Mechanism of Adsorption : `to` Adsorption arises due to the fact that the surface particles of the adsorbent are not in the same environment as the particles inside the bulk. `to` Adsorbent possess unbalanced or residual attractive forces. These forces responsible for attracting the adsorbate molecules on adsorbent surface. `to` The extent of adsorption increases with increase in surface area of adsorbent at a given temperature and pressure. `to` During the adsorption, there is always a decrease in residual forces of the surface. There is decrease in surface energy which appears as heat. So, Adsorption is always Exothermic. `to` Adsorption is accompanied by decrease in enthalpy as well as decrease in entropy of system. `to` As the adsorption proceeds `DeltaH` becomes less and less negative, ultimately, `DeltaH` becomes equal to `TDeltaS` and `DeltaG` becomes zero. At this state equilibrium is attained. |
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| 960. |
What is Gold number ? |
| Answer» The number of milligrams of a protective colloid required to prevent the coagulation of 10 ml Gold sol when 1 ml of 10% NaCl solution is added is called Gold number. | |
| 961. |
Three beams of white light passing through a colloid of sulphur particles in water change from orange to pink and blush green because the colour of colloidal solution depends on theA. wavelength of light scattered by the dispersed particles.B. size of the colloidal particlesC. position of viewersD. all of these |
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Answer» Correct Answer - D The colour of colloidal solution depends on the wavelength of light scattered by the dispersed particles. The wavelength of light further depends on the size and nature of the particles. The smaller the particles, the shorter (bluer) the wavelength. The colour of colloidal solution also changes with the manner in which the observer receive the light. For example, a mixture of milk and water appears blue when viewed by the reflected light and red when viewed by the transmitted light. Finest gold sol is red in colour but as the size of particles increase, it appears purple, then blue and finally golden. |
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| 962. |
On addition of one ml of 10% NaCl solution of 10ml gold sol in the presence of 0.25 gm of starch. The coagulation is just prevernted, starch had goldnumberA. 0.025B. 0.25C. 2.5D. None |
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Answer» Correct Answer - D `0.25xx1000=250`. |
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| 963. |
Sulphur colloid is prepared byA. mechanical dispersionB. OxidationC. Electrical dispersionD. Reduction |
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Answer» Correct Answer - B Sulphur sol is prepared by the oxidation of `H_(2)S` by bromine `Br_(2)+H_(2)Sto2HBrunderset((sol))(S)` |
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| 964. |
_______is the gold number of hydrophilic colloid, then greater is its protective power:-A. HigherB. LowerC. ConstantD. None of these |
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Answer» Correct Answer - B Lower the gold number of a protective colloid the greater is its protectively action. |
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| 965. |
Define the term adsorbate and adsorbent . |
| Answer» The substance which is absorbed is called absorbate. The substance on whose surface the adsorption take place is called adsorbent. | |
| 966. |
Cow milk is an example of natural emulsion stabilized byA. lactic acidB. lactoseC. caseinD. agar |
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Answer» Correct Answer - C Emulsions of oil in water are unstable and sometimes they separate into two layers on standing. For stabilization of an emulsion, a thired component called emulsifying agent is usually added. The emulsifying agent forms an interfacial film between suspended particles and the medium. Casein is a phosphoprotein which occurs in the milk of mam mals as a suspension of calcium caseinate. It is the main protein of milk. It can be obtained (as a pale yellow solid) from milk by treatment with mineral acid or rennett (or renin, the milk-clotting enzyme from the fourth stomach of ruminants) |
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| 967. |
Which is te wrong pair (i) starch solution:sol (ii) Aq NaCl: True solution (iii). Milk: emulsion (iv). Aq `BaSO_(4)`:true solutionA. (i)B. (iii)C. (iv)D. (ii) |
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Answer» Correct Answer - C `BaSO_(4)` is sparingly soluble salt hence it is not a true solution. |
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| 968. |
Name the type of emulsion to which milk belongs. |
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Answer» Milk is a oil in water type of emulsion. Dispersed phase : liquid fat. Dispersion medium : water. |
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| 969. |
Adsorbed due to strong chemical forcess is called :A. chemisorptionB. physisorptionC. both (a) and (b)D. none of these |
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Answer» Correct Answer - a |
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| 970. |
absorbed acetic acid on activated carban is :A. adsorberB. absorberC. adsorbentD. adsorbate |
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Answer» Correct Answer - d |
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| 971. |
Heterogeneous catalysis is successfully explained by………………. Theory. |
| Answer» Correct Answer - Adsorption isobar | |
| 972. |
Intermediate compound formation theory explans…………………. Catalysis. |
| Answer» Correct Answer - Homegeneous | |
| 973. |
Which of the following is/are the characteristic of a catalyst?A. It changes equilibrium pointB. It alter the rate of reactionC. It initiates the reactionD. It increases the average `KE` of molecules |
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Answer» Correct Answer - B::C::D Catalyst does not change the equilibrium.Correct Answer - B::C::D Catalyst does not change the equilibrium. |
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| 974. |
Rough surfaces have more…………. Centres on account of free valencies. |
| Answer» Correct Answer - Active | |
| 975. |
Which one of the followings is/are an example of homogeneous catalysis?A. Formation of `SO_(3)` in the chamber process.B. Formation of `SO_(3)` in the contact process.C. Hydrolysis of an ester in the present of acid.D. Decomposition of `KClO_(3)` in the presence on Manganese Dioxide |
| Answer» Correct Answer - A::C::DCorrect Answer - A::C::D | |
| 976. |
Which is/are correct statements?A. Physical adsorption always increases when temperature increasesB. Physical adsorption decreases when temperature increasesC. Chemical adsorption is reversibleD. Monolayer is formed is chemical adsorption |
| Answer» Correct Answer - B::D | |
| 977. |
A catalyst promoter……….. The efficiency of a catalyst while a poison…………….. The efficiency of the catalyst. |
| Answer» Correct Answer - Increases, decreases | |
| 978. |
Match the column I with Column II and mark the appropriate choice. A. `(A) to (i), (B) to (iii), (C) to (ii), (D) to(iv)`B. `(A) to (ii), (B) to (iii), (C) to (i), (D) to(iv)`C. `(A) to (iii), (B) to (i), (C) to (iv), (D) to(ii)`D. `(A) to (iv), (B) to (i), (C) to (iii), (D) to(ii)` |
| Answer» Correct Answer - C | |
| 979. |
Efficiency of the catalyst does not depend on its?A. Molecular weightB. Number of free valenciesC. Physical stateD. Amount used |
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Answer» Correct Answer - A::C::D Efficiency of catalyst depends upon the number of free valencies. Correct Answer - A::C::D Efficiency of catalyst depends upon the number of free valencies. |
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| 980. |
Which of the following is/are application(s) of adsorption?A. Adsorption indicatorsB. Thin layer chromatographyC. Qualitative analysisD. All of these. |
| Answer» Correct Answer - D | |
| 981. |
Which is/are application (s) of adsorption?A. Humidity can be controlled by adsorptionB. Inert gases cannot be separated by adsorptionC. Softening of hard Water takes place by adsorptionD. Colouring matter can be removed from the solution by adsorption |
| Answer» Correct Answer - A::C::D | |
| 982. |
Which of the following is/are application(s) of adsorption?A. De-ionization of waterB. Gas masksC. Hygroscopic nature of `CaCl_(2)`D. Heterogeneous catalysis |
| Answer» Correct Answer - A::B::DCorrect Answer - A::B::D | |
| 983. |
Wchich is/are correct statement?A. Lyophilic colloids are irreversibleB. Lyophilic colloids do not migrate in electric field or migrate in any directionC. In lyophobic colloids no hydration takes placeD. Lyophilic are more stable and lyophobic less stable |
| Answer» Correct Answer - B::C::D | |
| 984. |
Which of the following is the best protective colloid?A. Gelatin (Gold no=0.005)B. Gum arabic (Gold No.=0.15)C. Egg albumin (Gold No.=0.08)D. None of these |
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Answer» Correct Answer - A Protective power`prop(1)/("Gold number")` Thus gelatin is the best protective colloid. |
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| 985. |
Toilet soap is a mixture ofA. Calcium and sodium salts of fatty acidsB. Fatty acids and glycerolC. Sodium salts of fatty acidsD. Potassium salt of fatty acids |
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Answer» Correct Answer - D Toilet soap is a mixture of potassium salt of higher fatty acids. |
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| 986. |
Tyndall effect is not observed inA. SuspensionB. True solutionC. ElmulsionsD. Colloidal solution |
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Answer» Correct Answer - B Tyndall effect is observed for colloidal solution. |
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| 987. |
The process of passing of a precipitate into colloidal solution on adding an electrolyte is calledA. coaguationB. electrolysisC. diffusionD. peptization |
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Answer» Correct Answer - D is the correct answer. |
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| 988. |
If x gram of gas is adsobed by m gram of adsorbent at pressure P the plot of log `(x)/(m)` versus log P is linear .the slope of the plot is : (n and k are constant and n `gt` 1)A. `2 k`B. log kC. nD. `(1)/(n)` |
| Answer» Correct Answer - D | |
| 989. |
Which one of the following is not a property of physical adsorption ?A. Higher the pressure, more the adsorptionB. Greater the surface area, more the adsorptionC. Lower the temperature, more the adsorptionD. Unilayer adsorption occurs |
| Answer» Correct Answer - D | |
| 990. |
Which of the following statement is falseA. Every solid substance can be brought into colloidal stateB. Colloidal particles caryy electrical chargesC. Every solid substance can be made to behave like a lyophilic colloidD. Addition of electrolytes causes flocculation of colloidal particles |
| Answer» Correct Answer - C | |
| 991. |
The impurities present in rain water possess ……..charge.A. PositiveB. NegativeC. ZeroD. Positive and negative |
| Answer» Correct Answer - B | |
| 992. |
Gold number is the index forA. `AuCl_(3)`B. `NaCl`C. `AlCl_(3)`D. `FeCl_(3)` |
| Answer» Correct Answer - B | |
| 993. |
At high concentration of soap in water, soap behaves as …… .A. FoamB. GelC. GasD. Air |
| Answer» Correct Answer - B | |
| 994. |
Which of the following will show Tyndall effect?A. Aqueous solution of soap below critical micelle concentrationB. Aqueous solution of soap above critical micelle concentrationC. Aqueous solution of sodium chlorideD. Aqueous solution of sugar |
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Answer» Correct Answer - B Aqueous solution of soap above critical micelle concentration forms colloidal solution which shows Tyndall effect. |
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| 995. |
Correct eqution of Freundlich isotherm is :A. `log((x)/(m))=logK+(1)/(n)logC`B. `log((x)/(m))=logm+(1)/(m)logC`C. `log((x)/(m))=logC+(1)/(K)logC`D. `log((x)/(m))=logC+(1)/(n)logK` |
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Answer» Correct Answer - A |
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| 996. |
Spontaneous adsorption of a gas on solid surface is an exothermic process becauseA. enthalpy of the system increases.B. entropy increases.C. entropy decreases.D. free energy change increases. |
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Answer» Correct Answer - C |
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| 997. |
Spontaneous adsorption of a gas on solid surface is an exothermic process becauseA. `Delta H` increases for systemB. `Delta S` increases for gasC. `Delta S` decreases for gasD. `Delta G` increases for gas |
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Answer» Correct Answer - C |
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| 998. |
Which of the following interface cannot be obtained?A. Liquid-LiquidB. Solid-LiquidC. Liquid-GasD. Gas-Gas |
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Answer» Correct Answer - D |
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| 999. |
Adsorption, if spontaneous, is exothermic. Explain. |
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Answer» Adsorption is accompanied by decrease in entropy, i.e., `DeltaS=-ve` . If it is spontaneous than `DeltaG` should be negative `DeltaG=DeltaH-TDeltaS` . Since `DeltaS` is -ve (entropy decreases in the process of adsorption), `deltaG` will be negative, only if `DeltaH=-ve` , i.e., if the process is exothermic. Adsorption is accompanied by decrease in entropy, i.e., `DeltaS=-ve` . If it is spontaneous than `DeltaG` should be negative `DeltaG=DeltaH-TDeltaS` . Since `DeltaS` is -ve (entropy decreases in the process of adsorption), `deltaG` will be negative, only if `DeltaH=-ve` , i.e., if the process is exothermic. |
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| 1000. |
Which of the following statement is true regarding chemosorption of gas on the solid surfaceA. This type of adsorption ofirst increases with rise in temperatureB. No compoundformation takes plac in this caseC. The forces operting are weak van der Waals forceD. If forms multimolecular layer of as molculse on the surface of the solid. |
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Answer» Correct Answer - A Chemisorption involves strong valence bond force and is monolayered. It first increases with the ride in temperature and then starts decreasing. For details, consult section 5. |
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