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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.
| 701. |
Write the chemical formula of positively charged and negatively charged hydrated ferrlc oxide colloidal solutions. |
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Answer» `to` Formula of positively charged hydrated ferric oxide is `Fe_(2)O_(3).xH_(2)O""//Fe^(+3)` `to ` Formula of negatively charged hydrated ferric oxide is `Fe_(2)O_(3).xH_(2)O""//OH^(-)` |
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| 702. |
Electrokinetic potential (or zeta potential) is theA. potential difference between the fixed layer and the diffused layer of opposite chargesB. potential energy of colloidal particlesC. potential required to bring about coagulation of a colloidal sol.D. potential required to give the particles a speed of `1 cm//sec` in the sol |
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Answer» Correct Answer - A Consider the formation of silver iodide sol from the double decomposition reaction: `AgNO_(3)(aq.)+KI(aq.)rarrAgI(s)darr+KNO_(3)` Suppose that the electrolyte used in excess is potassium iodide. This would result in preferential adsorpition of `I^(-)` ions giving a negatively charged sol of silver iodide. The ions preferentially adsorbed on the surface of colloidal particles are called potential-determining ions. Having acquired a position or negative charge by selective adsorption on the surface of colloidal particles, this layer attracts counter ions from the dispersion medium forming a second layer: `AgI//I^(-)K^(+) AgI//Ag^(+)I^(-)` The combination of the two layers of opposite charges around the colloidal particle is called Helmholtz electrical double layer. According to modern views, the first layer of ions is firmly held and is termed fixed layer while the second layer is mobile which is termed diffused layer. Since separation of charge is a seat of potential, the charges of opposite signs on the fixed and diffused parts result in a difference in potential between these layers. This potential difference between the fixed layer and diffused layer of opposite charges is called the electrokinetic potential or zeta potential. The presence of equal and similar charges on colloidal particles is largely responsible in providing stability to the colloidal solution be cause the repulsive forces between chaged particles having same charge prevent them from coalecing or aggregating when they come closer to one another. |
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| 703. |
What is electrokinetic potential or zeta potential ? |
| Answer» In a colloidal sol the charges of opposite signs on the fixed and diffused parts of the double layer results in a difference in potential between these layers. The potential difference between the fixed layer and the diffused layer of opposite charge is called electro kinetic potential (or) zeta potential. | |
| 704. |
Zeta potential is the potential difference betweenA. Any two colloidal particles having opposite chargesB. The fixed layer and the diffused layer having same chargesC. The layer of adorbed ions and the mobile layer having opposite chargesD. Two colloidal layers having same charges |
| Answer» Correct Answer - C | |
| 705. |
Which of the following are based on Tyndall effect.A. UltramicroscopeB. DeltasC. Blue colour of skyD. Coagulation |
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Answer» Correct Answer - A::C Ultramicroscope (c) Blue colour of sky is due to Tyndall effect. (b) and (d) are not possible. |
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| 706. |
For the study of catalystic reaction who was awarded noble prizeA. OstwaldB. BerziliusC. Vant HoffD. Werner |
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Answer» Correct Answer - A ostwald was awarded 1909 Chemistry Noble prize in the field of catalysis. |
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| 707. |
In the aqueous solution of soaps above :A. the cations associate to form the aggregatesB. the anions associate to from the clusters of colloidal dimensionC. the polar ends of the clusters of colloidal dimensionD. the non - polar ends (hydrocarbon) ends are directed toward water |
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Answer» Correct Answer - a,b |
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| 708. |
When negatively charged colloids like `As_(2)S_(3)` sol is added to positively charged `Fe(OH)_(3)` sol in suitable amountsA. Both the sols are precipitated simultaneouslyB. This process is called mutually coagulationC. They becomes +vely charged colloidD. They become -vely charged colloid |
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Answer» Correct Answer - A::B both will get coagulated due to neutralization of charge. (b) is charge (c) and (d) are not possible, because they become neutral. |
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| 709. |
Colloidal solution can be purified by :A. dialysisB. electrodialysisC. electrophoresisD. ultrafiltration |
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Answer» Correct Answer - a,b,c |
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| 710. |
Define zeta, potential. |
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Answer» The potential difference set up between electrical double layer of opposite charge is called zeta potential. |
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| 711. |
which are the properties of colloidal solution ?A. AdsorptionB. Tyndall effectC. FlocculationD. Depression of freezing point |
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Answer» Correct Answer - b,c |
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| 712. |
Coagulation of colloids can be achieved by :A. CentrifugationB. Adding electrlyteC. Change in pHD. Adding water |
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Answer» Correct Answer - A::B::C Coagulation of lyophilic sols like milk can be coagulated by centrifugation. ltBrgt (b) Lyophobic sols can be coagulated by adding electrolyte. (c) Lyophiolic sols like egg albumin are coagulated by change in pH (d) Adding water cannot lead to coagulation. |
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| 713. |
Which of the following reaction is catalysed by enzyme maltaseA. Starch`to`maltoseB. Maltose`to`glucoseC. Lactose`to`maltoseD. Maltose`to`glucose+fructose |
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Answer» Correct Answer - B Maltose`underset("enzyme")overset("Maltose")to`Glucose |
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| 714. |
Coagulation of colloids can be achieved by :A. centrifugationB. adding electrolyteC. change in PHD. adding water |
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Answer» Correct Answer - a,b,c,d |
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| 715. |
How lyophobic colloids prevented from coagulation? |
| Answer» By adding lyophilic collodis before the addition of electrolyte | |
| 716. |
A colloidal solution can be purified by the following method :A. FiltrationB. PeptizationC. CoagulationD. Dialysis |
| Answer» Correct Answer - D | |
| 717. |
Match the types of colloidal systems given in Column I with the name given in Column II. `{:(,"Column I","Column II"),(A.,"Solid in liquid",1."Foam"),(B.,"Liquid in solid ",2."Sol"),(C.,"Liquid in liquid ",3."Gel"),(D.,"Gas in liquid",4."Emulsion"):}` |
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Answer» Correct Answer - `A. to (2)` `B. to (3)` `C. to (4)` `D. to (1)` Colloids are classified on the basis of types of dispersed phase and dispersion medium. `{:(,"Dispersed phase ","Dispersion medium","Name"),(A.,"Solid in", "Liquid","Sol"),(B.,"Liquid in", "Solid ","Gel"),(C.,"Liquid in","Liquid ","Emulsion"),(D.,"Gas in","Liquid ","Foam"):}` |
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| 718. |
How mnay colloidal systems exist in nature in which gas is dispersed phase? |
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Answer» Correct Answer - 2 |
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| 719. |
How many colloidal systems exist in nature in which liquid a dispersed phase? |
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Answer» Correct Answer - 3 |
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| 720. |
How many colloidal systems exist in nature? |
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Answer» Correct Answer - 8 |
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| 721. |
each question constain STATEMENT-1(Assertion ) and STATEMENT - 2 (reason). examine the statement carefully and work the correct answer accoridng to the instructions given below :STATEMENT-1: Size of suspension particles are smaller than collidal particles.A. if both the statement are TRUE and STATEMENT -2 is the correct explanation of STATEMENT - 1B. If both the statement are STATEMENT -2 is NOT the correct explanation of STATEMENT -1C. If STATEMENT -1 is TRUE and STATEMENT is FALSED. If STATEMENT -1 is FALSE and STATEMENT -2 is TRUE |
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Answer» Correct Answer - C |
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| 722. |
each question constain STATEMENT-1(Assertion ) and STATEMENT - 2 (reason). examine the statement carefully and work the correct answer accoridng to the instructions given below :STATEMENT-1: A colloid gets coagulated by addition of an electrolytes. STATEMENT-2: Coagulation depends on the valance and sign of the charge of the coagulant ion.A. if both the statement are TRUE and STATEMENT -2 is the correct explanation of STATEMENT - 1B. If both the statement are STATEMENT -2 is NOT the correct explanation of STATEMENT -1C. If STATEMENT -1 is TRUE and STATEMENT is FALSED. If STATEMENT -1 is FALSE and STATEMENT -2 is TRUE |
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Answer» Correct Answer - B |
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| 723. |
each question constain STATEMENT-1(Assertion ) and STATEMENT - 2 (reason). examine the statement carefully and work the correct answer accoridng to the instructions given below :STATEMENT-1: Colloidal solutions are stable but colloidal particles do not settle down. STATEMENT-2: Brownian movement counters the force of gravity act on collooidal particlesA. if both the statement are TRUE and STATEMENT -2 is the correct explanation of STATEMENT - 1B. If both the statement are STATEMENT -2 is NOT the correct explanation of STATEMENT -1C. If STATEMENT -1 is TRUE and STATEMENT is FALSED. If STATEMENT -1 is FALSE and STATEMENT -2 is TRUE |
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Answer» Correct Answer - A |
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| 724. |
select thee correct statement (S)A. physical adsorption is specific in natureB. chemical adsorption highly specific in natureC. physical adsorption is due to free valence of atomsD. chemical adsoption is due to stronger interaction or bond formation |
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Answer» Correct Answer - b,d |
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| 725. |
select the correct statement (s) :A. Benzene is dispersed phase in benzosolB. sols are irreversible and not so tableC. sol can be produced by double decompostionD. when a solution in alcohol is added in excess of water a sol of alcohol is formed |
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Answer» Correct Answer - a,b |
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| 726. |
which of the following is/ are correct for sols ?A. Its surface tension is lower than that of waterB. Its viscosity is higher than that of waterC. Its surface tension is higher than that of waterD. Its viscority is equal to that of water |
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Answer» Correct Answer - b,c |
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| 727. |
which of the following is not ?A. Gelatin solB. Silver solC. Sulphur solD. `As_(2)S_(3)` sol |
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Answer» Correct Answer - a,b |
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| 728. |
select the correct statement (s) :A. adsorption is a non - spontyaneous processB. surface energy deceases during the process of adsorptionC. adsorption takes place with decrease of entropyD. in general adsoption is exothermic process |
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Answer» Correct Answer - b,c,d |
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| 729. |
select the correct statement (s):A. physisorption is favoured by low temperatureB. chemisorption is favoured by very high temperauture becouse the process is endothemicC. chemisorption increase with increases in temperature owing to high activation energyD. Oxygen adsorbed by charcol can be desorbed by lowing pressure and temperture |
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Answer» Correct Answer - a,c,d |
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| 730. |
which of the following are colloids ?A. Sulphur solB. starchC. Gold solD. soap solution |
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Answer» Correct Answer - b,c,d |
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| 731. |
How does the extent of adsorption depend upon Increasing temperature of the system. |
| Answer» The extent of adsorption decreases with an increase in temperature. | |
| 732. |
How does the extent of adsorption depend upon Increasing pressure of the gas. |
| Answer» The extent of adsorption increases with increasing pressure of the gas. | |
| 733. |
Discuss some features of catalysis by zeolites. |
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Answer» `to` The catalytic reaction that depends upon the pore structure of the catalyst and the size of the reactant and product molecules is called shape selective catalysts. `to` Zeolites are shope selective catalysts because of their honey comb-like structure. They are microporous alumino silicates with 3-dimensional net work of silicates. `to` Zeolites are microporous alumino silicates with dimensional network of silicates in which some Si-atoms are replaced by aluminium atoms giving Al -O-Si frame work `to` The reactions taking place in zeolites depend upon the size and shape of reactant and product molecules as well as on the pores and cavities of the zeolites. `to` Zeolites are found in nature and also synthesized for catalytic selectivity. Uses : `to` Zeolities are used as catalysts in petrochemical industries for cracking. `to` Zeolite ZSM -5 is used to covert alcohol directly into gasoline (petrol) by dehydrating them to give a mixture of hydrocarbons. |
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| 734. |
the heat evolved in physisorption lies in the range (in kJ/mol) of :A. 20 - 40B. 40- 100C. 100 - 200D. 200 - 400 |
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Answer» Correct Answer - a |
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| 735. |
According to the adsoption theory of catalysis ,the speed of the reaction increases because:A. in the process of adsorption , the activation energy of the molecules becomes largeB. adsorption produces heat which increases the speed of the reactionC. adsorption lowers the activation energy of the reactionD. adsorption increases the activation energy of the reaction |
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Answer» Correct Answer - c |
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| 736. |
Which of the following statements of correct for the spontaneous adsoption of a gas?A. `DeltaS` is negative and therefore, `DeltaH` should be highly positiveB. `DeltaS` is negative and therefore, `DeltaH` should be highly negativeC. `DeltaS` is positive and therefore, `DeltaH` should be negativeD. `DeltaS` is positive and therefore, `DeltaH` should also be highly positive |
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Answer» Correct Answer - B `DeltaS` [change in entropy] and `DeltaH` [change in enthalpy are related by the equation `DeltaG = DeltaH - TDeltaS` [Here, `DeltaG` = change in Gibbs free energy] For adsorption of a gas, `DeltaS` is negative because randomness decreases. Thus, in order to make `DeltaG` negative [for spontaneous reaction]. `DeltaH` must be highly negative because reaction is exothermic. Hence, for the adsorption of a gas, if `DeltaS` is negative, therefore, `DeltaH` should be highly negative, therefore, `DeltaH` should be highly negative. |
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| 737. |
The protcting power of lyophilic colloidal solution is expressed in terms ofA. Critical numberB. Oxidation numberC. Coagulation valueD. Gold number |
| Answer» Correct Answer - D | |
| 738. |
In frenudlich adsorption isotherm, the value of `1//n` isA. between 0 and 1 in all casesB. between 2 and 4 in all casesC. 1 in cases of physical adsorptionD. 1 in case of chemisorption |
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Answer» Correct Answer - A In Freundlich adsorption isotherm, `(x)/(m)= kp^(1//n)` Where, x = amount of adsorbent m = amount of adsorbate The value of n is always greater than 1. So, the value of 1/n lies between 0 and 1 in all cases. |
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| 739. |
The protcting power of lyophilic colloidal solution is expressed in terms ofA. coagulation valueB. gold numberC. crititcal micelle concentrationD. oxidation number |
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Answer» Correct Answer - B Lyophobic sols are unstable, so they are stabilised by adding some lyophilic colloids which protect them from precipitation. Thus, lyophilic colloids are called protecting colloids. Their protecting power is expressed in terms of gold number. In other words, gold number can be defined as the minimum amount of lyophilic colloid in milligrams, which prevent the flocculation of 10 mL gold sol by the addition of 1 mL of 10% NaCl solution. NOTE Lesser the gold number, higher is the protecting power. |
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| 740. |
In frenudlich adsorption isotherm, the value of `1//n` isA. 1 in case of physical adsorptionB. 1 in case of chemisorptionC. between 0 and 1 in all caseD. between 2 and 4 in all cases |
| Answer» Correct Answer - C | |
| 741. |
In frenudlich adsorption isotherm, the value of `1//n` isA. between `0` and `1` in all casesB. between `(2)` and `(4)` in all casesC. `1` in cases of physical adsorptionD. `1` in cases of chemisorption |
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Answer» Correct Answer - A According to Freundlich adsorption isotherm, we have `(x)/(m)=kP^(1//n)` when `1//n` is `1` for low pressure region but `0` for high pressure region. |
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| 742. |
In frenudlich adsorption isotherm, the value of `1//n` isA. `1` in case of physical adsorptionB. `1` in case of chemisorptionC. between `0` and `1` in all casesD. between `2` and `4` in all cases |
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Answer» Correct Answer - C Freundlich adsorption isotherm is `X/m = KP^(1//n)` If `P rarr 0, n=1 :. (X)/(m) = KP` if `P` is high , `n=0 :. (X)/(m) = KP^(0)`. |
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| 743. |
Which one of the following statements is incorrect about enzyme catalysis?A. Enzymes are mostly proteinous in natureB. Enzyme action is specificC. Enzymes are denatured by ultraviolet rays and at high temperatureD. Enzymes are least reactive at optimum temperature. |
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Answer» Correct Answer - D The rate of an enzyme reaction becomes maximum at a definite temperature, called the optimum temperature. On either side of the optimum temperature. The enzyme activety decreases. The optimum temperature range for enzymatic activity is `298-301K` . Human body temperature being `310K` is thus suited for enzyme-cataysed reactions. |
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| 744. |
Which one of the following statements is incorrect about enzyme catalysis?A. Enzymes are denatured by ultraviolet rays and at high tempetaure.B. Enzymes are least reactive at optimum temperature.C. Enzymes are mostly proteinous in nature.D. Enzyme action is specific. |
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Answer» Correct Answer - B Enzymes are least reactive at optimum temperature. |
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| 745. |
In physical adsorption, the molecules of adsorbate are held by chemical forces. |
| Answer» Correct Answer - F | |
| 746. |
Which one of the following statements is incorrect about enzyme catalysis?A. Enzymes are mostly proteinous in natureB. Enzyme action is specificC. Enzymes are denaturated by UV-rays and at high temperatureD. Enzymes are least reactive at optimum temperature |
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Answer» Correct Answer - D Most of the enzymes have proteinous nature. They are highly specific and get denaturated by high temperature or UV-rays. At optimum temperature, which is generally in between `25^(@)-35^(@)C`, enzyme activity is maximum. |
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| 747. |
Actication energy is always lowered by positive catalyst. |
| Answer» Correct Answer - T | |
| 748. |
For the coagulation of `10 mL` of `Fe(OH)_(3) sol, 2 mL` of `1 M KBr` is required. What is the flocculation value of `KBr`? |
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Answer» `2mL` of `1MKBr` contans `KBr=(1)/(1000)xx2mol=2m mol` Thus, `10mL` of `Fe(OH)_(3)` sol requires `KBr` for complete coagulation `=2m mol` `:. 1L,` i.e., `1000mL,` of the sol requires `KBr` for complete coagulation `=200m mol` Hence, flocculation value of `KBr=200` `2mL` of `1MKBr` contans `KBr=(1)/(1000)xx2mol=2m mol` Thus, `10mL` of `Fe(OH)_(3)` sol requires `KBr` for complete coagulation `=2m mol` `:. 1L,` i.e., `1000mL,` of the sol requires `KBr` for complete coagulation `=200m mol` Hence, flocculation value of `KBr=200` |
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| 749. |
Which of the following is not correct for enzyme catalysis?A. The enzyme activity is maximum at optimum pH which is between 5-7B. Each enzyme is specific for a given reaction.C. The favourable temperature range of enzyme activity is between `50-60^(@)C` .D. The enzymatic activity is increased in presence of certain substances called co-enzymes. |
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Answer» Correct Answer - C The enzymatic activity is destroyed at about `70^(@)` C. The favourable temperature range for enzymatic activity is `25-27^(@)C`. |
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| 750. |
At `400K` , the energy of activation of a reaction is decreased by `0.8Kcal` in the presence of catalyst. Hence, the rate will be a. Increased by `2.73` times b. Increased by `1.18` times c. Decreased by `2.72` times d. Increased by `6.26` times |
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Answer» We know `(K_(2))/(K_(1))=` Antilog `[(DeltaE)/(2.303RT)]` Given `DeltaE=0.8Kcal=3.344xx10^(3)J` `R=8.314JK^(-1)mol^(-1)` `T=400K` Substituting all the values in Eq. (i), we get `(K_(2))/(K_(1))=` Antilog `[(3.344xx10^(3))/(8.314xx2.303xx400)]=2.73` `:. K_(2)=2.73K_(1)` Therefore, the rate will increase by `2.73` times. We know `(K_(2))/(K_(1))=` Antilog `[(DeltaE)/(2.303RT)]` Given `DeltaE=0.8Kcal=3.344xx10^(3)J` `R=8.314JK^(-1)mol^(-1)` `T=400K` Substituting all the values in Eq. (i), we get `(K_(2))/(K_(1))=` Antilog `[(3.344xx10^(3))/(8.314xx2.303xx400)]=2.73` `:. K_(2)=2.73K_(1)` Therefore, the rate will increase by `2.73` times. |
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