Tag: adsorption and colloids
Questions Related to adsorption and colloids
Silver iodide is used for producing artificial rains because $AgI$:
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is easy to spray at high altitude
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is insoluble in water
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is easy to synthesize
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has crystals similar to ice
Solid silver iodide is preferred as a nucleator for artificially stimulated rain because its crystal lattice parameters are close to those of ice, and for that reason are more effective than other salts in causing small ice crystals in clouds to melt.
To stop bleeding from an injury ferric chloride can be applied
Which comment about the statement is justified?
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It is not true, ferric chloride is a poison
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It is true, ${Fe}^{3+}$ ions coagulate blood which is negatively charged sol
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It is not true, ${Cl}^{-}$ ions from positively charged sol, profuse bleeding takes place
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It is true, coagulation takes place because of formation of negatively charged sol with ${Cl}^{-}$ ions.
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It is not true, ferric chloride is ionic and gets into blood stream
To stop bleeding from an injury, Ferric chloride can be applied because of the following reason:
(A) $Fe^{3+}$ ions coagulate blood which is a negatively charged solution
(B) $Cl^−$ ions coagulate blood which is a positively charged solution
Blood
being a colloidal solution, its coagulation by
Hardy-Shuze's law states " Higher the charge on cation higher will
be its efficiency to coagulate the colloidal solution" . Thus Option B is correct.
What is the role of adsorption in froth floatation process used especially for concentration of sulphide ores?
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Shape selective catalysts
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Adsorption of pine oil on sulphide ore particles
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Adsorption of pine oil on impurities
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Production of heat in the process of exothermic reaction
- In Froth floatation process a low-grade sulphide ore is concentrated by separating it from silica and other earthy matter by this method using pine oil and frothing agent.
- Pine oil is adsorbed on sulphide ore particles so as to facilitate the further process.
Which is not correct regarding the adsorption of a gas on surface of a solid?
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On increasing temp. adsorption increase continuously
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Enthalpy & entropy change is Ve
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Adsorption is more for some specific substance
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Reversible
Lake test of $Al^{3+}$ ion is based on adsorption of blue litmus on solid surface of :
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$Al$
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$Al(OH) _3$
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$Al _2O _3$
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$AlCl _3$
Lake test of $Al^{3+}$ ion is based on adsorption of blue litmus on solid surface of $Al(OH) _3$. The dye aluminon is adsorbed by the gelatinous $Al(OH) _3$ precipitate to form lake coloured solution. This test is used as a confirmatory test for $Al^{3+}$ after precipitation of $Al(OH) _3$ with aqueous ammonia.
Which of the following increase(s) the activation of a solid adsorbent?
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Polishing the surface of the solid adsorbent.
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Sub-dividing the solid adsorbent.
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Blowing superheated steam through the porous adsorbent.
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Adsorption at very low pressure.
Adsorption is the adhesion of atoms, ions or molecules from a gas, liquid, or dissolved solid to a surface.
Adsorption of gases on solids depends on the following factors:
Polishing the surface of the solid adsorbent makes no effect on adsorption.
Which of the following is/are application(s) of adsorption?
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De-ionization of water
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Gas masks
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Hygroscopic nature of $CaCl _2$
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Heterogeneous catalysis
In gas masks:
All gas masks are devices containing suitable adsorbent so that the poisonous gases present in the atmosphere are preferentially adsorbed and the air for breathing is purified.
In heterogeneous catalysis:
The action of certain solids as catalysts is best explained in terms of adsorption. The theory is called adsorption theory. According to this theory, the gaseous reactants are adsorbed on the surface of the solid catalyst. As a result, the concentration of the reactants increases on the surface and hence, the rate of reaction increases. The theory is also able to explain the greater efficiency of the catalyst in the finely divided state, the action of catalyst promoters and poisons.
In softening of hard water (De-ionization of water):
The use of ion exchangers for softening of hard water is based upon the principle of competing adsorption just as in chromatography. Hygroscopic nature of $CaCl _2$ is not related to adsorption.
Which of the following is used to adsorb water?
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Silica gel
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Calcium acetate
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Hair gel
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Cheese
Silica gel has a very strong affinity for water and will adsorb it in preference to most other substances. It is also a good adsorbent for HCl, gasoline-range hydrocarbons, sulphur and nitrogen compounds, aromatics and many others. Silica Gel is in wide use in many industries for a myriad number of applications where a high capacity desiccant or selective adsorbent is required.
State one method by which carbon dioxide is removed from the air?
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Absorption method
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Distillation method
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Adsorption method
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None of these
In physical adsorption Zeolite(A/B)'s applications are seperation of n-paraffins and i paraffins etc.
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True
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False
There are several commercial applications based on this mechanism in adsorptive separation processes. One typical example is separating normal paraffin from iso-paraffin and aromatics in an adsorption process using zeolite 5A as an adsorbent.