When FeCl3 is dissolved in hot water, hydrated ferric oxide forms. This highly hydrated oxide hydrate adsorbs Fe3+ ions results in a positively charged colloid.
Why do physisorption and chemisorption behave differently with rising in temperature?
1. In physisorption, with increasing temperature, the bond between adsorbent and adsorbate weakens and the amount of adsorbate decreases. 2. In chemisorption, the amount of activation energy needed...
What happens when dialysis is prolonged?
If dialysis continues for a long time, the electrolyte deposits present in the blood are also completely removed and blood coagulation is established.
Why does the white precipitate of silver halide become coloured in the presence of dye eosin?
The silver halide surface acts as a good adsorbent. It can be able to adsorb the pigment present in the eosin dye. So, the silver halide seems to be colored.
What is the role of activated charcoal in a gas mask used in coal mines?
The activated charcoal works as a good adsorbent because it is porous. Because of this, in the coal mines, it is used to provide fresh air for the breathing purpose via a gas mask.
How will you distinguish between the dispersed phase and dispersion medium in an emulsion?
Emulsion is the dispersion of one liquid into another invisible liquid. The dispersed phase is always available in lesser amount when compared to the dispersion medium.
Based on Hardy-Schulze rule explain why the coagulating power of phosphate is higher than chloride.
According to Hardy-Schulze law, electrolyte coagulation properties depend on the valency of coagulation ion. The higher the charge in flocculating ion the smaller the amount of electrolyte required...
Why does the bleeding stop by rubbing moist alum?
Moist alum is highly charged with Al3+ and SO42-ions which activate the charged protein molecules present in the blood. This causes the blood protein to coagulate and stops bleeding.
How does the precipitation of colloidal smoke take place in Cottrell precipitator?
The Cottrell precipitator is a filtering tool that removes fine particles such as dust and fumes from flowing electricity. It neutralizes the charge on carbon particles.
Why does leather get hardened after tanning?
When the skin is soaked in tannin, coagulation occurs as a result of a combination of animal skin (positively charged) and tannin (negatively charged). Thus resulting in the hardening of the leather...
Why are some medicines more effective in the colloidal form?
The colloidal solution has a larger surface area than the true solution. The surface area is directly proportional to the level of assimilation in our body. So, the drugs work effectively when...
How do emulsifying agents stabilise the emulsion?
1. Emulsifying agents stabilize the emulsion by forming interfacial film between the suspended particles and the dispersion medium. 2. Example: Agar (used in foods)
A colloid is formed by adding FeCl3 in excess of hot water. What will happen if excess sodium chloride is added to this colloid?
FeCl3 when dissolved in hot water, forms hydrated ferric oxide, a sol which is positively charged due to the absorption of Fe3+ ions. By adding NaCl, the negatively charged chloride ions reduce the...
What causes Brownian motion in colloidal dispersion?
1. The Brownian motion occurs because of the collision between the colloidal particles and dispersion medium. 2. The movement causes the stability of the colloidal solution.
What happens when the electric field is applied to a colloidal solution?
When an electric field is applied to a colloidal solution, the colloidal particles move to different electrodes depending on their charge.
Why do we add alum to purify water?
1. Alum is basically the potassium aluminum sulphate [KAl(SO4)2]. 2. When dissolved in alkaline bicarbonate it forms a gelatinous precipitate. 3. When added to water it attracts colloidal particles...
What is collodion?
Collodion: 1. Collodion is a 4% solution of nitrocellulose prepared in a mixture of alcohol and ether. 2. Collodion is a solution which is syrupy in texture and can be inflammable.
Gelatin which is a peptide is added in icecreams. What can be its role?
Gelatin acts as an emulsifying agent for hydrophilic colloid. They absorb water content from ice cream and are also a good source of protein. They also give a soft texture and a glossy appearance to...
Why is it important to have a clean surface in surface studies?
The surface of the adsorbent adsorbs the gases that are desirable in the process of adsorption. If an area already has other gases, it is saturated so it cannot adsorb the desired gases from the...
Why is chemisorption referred to as activated adsorption?
Chemisorption involves the formation of chemical bonds that require activating energy. That's why it's called activated adsorption.
What type of solutions are formed on dissolving different concentrations of soap in the water?
The soap solution at low concentration acts as a standard electrolytic solution. But in the higher concentrations it behaves like a colloid and forms micelles.
What happens when gelatin is mixed with gold sol?
When the gelatin is mixed with gold sol, the gelatin forms a protective layer on the gold sol, thus preventing it from getting coagulated. So gold sol recovers by adding gelatin, which is a...
How does it become possible to cause artificial rain by spraying silver iodide on the clouds?
The Clouds hold charges as they are colloids. Silver iodide (AgI) electrolyte assists in the process of coagulation between colloidal water particles in a cloud. Thus, forming large raindrops that...
Which of the following phenomenon occurs when a chalk stick is dipped in ink?
(i) adsorption of coloured substance (ii) adsorption of solvent (iii) absorption and adsorption both of solvent (iv) absorption of solvent Correct Answers: (i) adsorption of coloured...
In a reaction, catalyst changes ____________.
(i) physically (ii) qualitatively (iii) chemically (iv) quantitatively Correct Answers: (i) physically (ii) qualitatively Explanation: In a reaction, catalyst changes physically and...
Which phenomenon occurs when an electric field is applied to a colloidal solution and electrophoresis is prevented?
(i) Reverse osmosis takes place. (ii) Electro osmosis takes place. (iii) Dispersion medium begins to move. (iv) Dispersion medium becomes stationary. Correct Answers: (ii) Electro osmosis...
What happens when a lyophilic sol is added to a lyophobic sol?
(i) Lyophobic sol is protected. (ii) Lyophilic sol is protected. (iii) Film of lyophilic sol is formed over lyophobic sol. (iv) Film of lyophobic sol is formed over lyophilic sol. Correct...
Which of the following colloids cannot be coagulated easily?
(i) Lyophobic colloids. (ii) Irreversible colloids. (iii) Reversible colloids. (iv) Lyophilic colloids. Correct Answers: (iii) Reversible colloids. (iv) Lyophilic colloids. Explanation:...
Which of the following substances will precipitate the negatively charged emulsions?
(i) KCl (ii) glucose (iii) urea (iv) NaCl Correct Answers: (i) KCl (iv) NaCl Explanation: KCl and NaCl are the substances that can precipitate the negatively charged...
An emulsion cannot be broken by __________ and ___________.
(i) heating (ii) adding more amount of dispersion medium (iii) freezing (iv) adding emulsifying agent Correct Answers: (ii) adding more amount of dispersion medium (iv) adding emulsifying...
Which of the following statements are correct?
(i) Mixing two oppositely charged sols neutralises their charges and stabilises the colloid. (ii) Presence of equal and similar charges on colloidal particles provides stability to the colloids....
H2 gas is adsorbed on activated charcoal to a very little extent in comparison to easily liquefiable gases due to ____________.
(i) very strong van der Waal’s interaction. (ii) very weak van der Waals forces. (iii) very low critical temperature. (iv) very high critical temperature. Correct Answers: (ii) very weak van...
Freundlich adsorption isotherm is given by the expression x/m = kp1/n which of the following conclusions can be drawn from this expression
(i) When1/n= 0, the adsorption is independent of pressure. (ii) When 1/n = 0, the adsorption is directly proportional to pressure. (iii)When n = 0,x/m vs p graph is a line parallel to x-axis. (iv)...
Which of the following statements are correct about solid catalyst?
(i) Same reactants may give different product by using different catalysts. (ii) Catalyst does not change ∆H of reaction. (iii) Catalyst is required in large quantities to catalyse reactions. (iv)...
Which of the following option are correct?
(i) Micelle formation by soap in aqueous solution is possible at all temperatures. (ii) Micelle formation by soap in aqueous solution occurs above a particular concentration. (iii) On dilution of...
Which of the following phenomenon applies to the process shown in Figure?
(i) Absorption (ii) Adsorption (iii) Coagulation (iv) Emulsification Correct Answer: (ii) Adsorption Explanation: Adsorption is the process that can be applied to this...
Which of the following process is not responsible for the presence of electric charge on the sol particles?
(i) Electron capture by sol particles. (ii) Adsorption of ionic species from solution. (iii) Formation of Helmholtz electrical double layer. (iv) Absorption of ionic species from solution. ...
Which of the following curves is in accordance with Freundlich adsorption isotherm?
Correct Answer: Option (iii) Explanation: According to the Freundlich adsorption isotherm, the option (iii) represents the proper graph.
Which of the following process is responsible for the formation of the delta at a place where rivers meet the sea?
(i) Emulsification (ii) Colloid formation (iii) Coagulation (iv) Peptisation Correct Answer: (iii) Coagulation Explanation: The Coagulation is responsible for the formation of the delta at a...
Arrange the following diagrams in the correct sequence of steps involved in the mechanism of catalysis, in accordance with modern adsorption theory.
(i) a → b → c → d → e (ii) a → c → b → d → e (iii) a → c → b → e → d (iv) a → b → c → e → d Correct Answer: (ii) a → c → b → d → e Explanation: According to the modern adsorption theory, the...
The values of colligative properties of the colloidal solution are of small order in comparison to those shown by true solutions of same concentration because of colloidal particles __________________.
(i) exhibit an enormous surface area. (ii) remain suspended in the dispersion medium. (iii) form lyophilic colloids. (iv) are comparatively less in number Correct Answer: (iv) are...
A colloidal system having a solid substance as a dispersed phase and a liquid as a dispersion medium is classified as ____________.
(i) solid sol (ii) gel (iii) emulsion (iv) sol Correct Answer: (iv) sol Explanation: A colloidal system having a solid substance as a dispersed phase and a liquid as a dispersion medium is...
Which of the following electrolytes will have maximum coagulating value for AgI/Ag+ sol?
(i) Na2S (ii) Na3PO4 (iii) Na2SO4 (iv) NaCl Correct Answer: (ii) Na3PO4 Explanation: Na3PO4 is the electrolyte that has maximum coagulating value for AgI/Ag+ sol.
Freshly prepared precipitate sometimes gets converted to colloidal solution by ___________.
(i) coagulation (ii) electrolysis (iii) diffusion (iv) peptisation Correct Answer: (iv) peptisation Explanation: Freshly prepared precipitate sometimes gets converted to colloidal solution by...
The method by which lyophobic sol can be protected.
(i) By the addition of oppositely charged sol. (ii) By the addition of an electrolyte. (iii) By the addition of lyophilic sol. (iv) By boiling. Correct Answer: (iii) By the addition of...
Which of the following will show the Tyndall effect?
(i) An aqueous solution of soap below critical micelle concentration. (ii) An aqueous solution of soap above critical micelle concentration. (iii) An aqueous solution of sodium chloride. (iv) An...
At high concentration of soap in water, soap behaves as ____________.
(i) molecular colloid (ii) associated colloid (iii) macromolecular colloid (iv) lyophilic colloid Correct Answer: (ii) associated colloid Explanation: At high concentration of soap in water,...
In which of the following reactions heterogeneous catalysis is involved?
(a) 2SO2(g) + O2(g)→ [NO(g)] 2SO3(g) (b) 2SO2(g) → [Pt(s)] 2SO3(g) (c) N2(g) + 3H2(g) → [Fe(s)] 2NH3(g) (d) CH3COOCH3(l) + H2O (l) → [HCl(l)] CH3COOH (aq) + CH3OH (aq) Correct Answer: (a)...
Based on data given below to predict which of the following gases shows the least adsorption on a definite amount of charcoal?
Gas Critical temo./K CO2304 SO2630 CH4190 H233 (i) CO2 (ii) SO2 (iii) CH4 (iv) H2 Correct Answer: (iv) H2 Explanation: H2 is the gas that shows the least adsorption on a definite amount of...
Which of the following an example of absorption?
(i) Water on silica gel (ii) Water on calcium chloride (iii) Hydrogen on finely divided nickel (iv) Oxygen on the metal surface Correct Answer: (ii) Water on calcium chloride Explanation:...
In physisorption adsorbent does not show specificity for any particular gas because ______________.
(i) involved van der Waals forces are universal. (ii) gases involved behave like ideal gases. (iii) enthalpy of adsorption is low. (iv) it is a reversible process. Correct Answer: (i)...
Physical adsorption of a gaseous species may change to chemical adsorption with ______________.
(i) decrease in temperature (ii) increase in temperature (iii) increase in surface area of the adsorbent (iv) the decrease in surface area of the adsorbent Correct Answer: (ii) increase in...
Which of the following is not a favourable condition for physical adsorption?
(i) high pressure (ii) negative ∆H (iii) the higher critical temperature of adsorbate (iv) high temperature Correct Answer: (iv) high temperature Explanation: The high temperature is not a...
Which one of the following is not applicable to the phenomenon of adsorption?
(i) ∆H > 0 (ii) ∆G < 0 (iii) ∆S < 0 (iv) ∆H < 0 Correct Answer: (i) ∆H > 0 Explanation: ∆H > 0 is not applicable to the phenomenon of adsorption.
The extent of adsorption of adsorbate from the solution phase increases with ________.
(i) increase in the amount of adsorbate in solution. (ii) the decrease in surface area of the adsorbent. (iii) increase in temperature of the solution. (iv) the decrease in the amount of adsorbate...
Extent of physisorption of a gas increases with ___________.
(i) increase in temperature. (ii) the decrease in temperature. (iii) the decrease in surface area of the adsorbent. (iv) the decrease in strength of van der Waals forces. Correct Answer: (ii)...
The term ‘sorption’ stands for ____________.
(i) absorption (ii) adsorption (iii) both absorption and adsorption (iv) desorption Correct Answer: (iii) both absorption and adsorption Explanation: SORPTION - Both absorption and...
Which of the following interface cannot be obtained?
(i) liquid-liquid (ii) solid-liquid (iii) liquid-gas (iv) gas-gas Correct Answer:(iv) gas-gas Explanation: The gas-gas interface cannot be obtained.
At the equilibrium position in the process of adsorption ___________.
(i) ∆H > 0 (ii) ∆H = T∆S (iii) ∆H > T∆S (iv) ∆H < T∆S Correct Answer: (ii) ∆H = T∆S Explanation: At the equilibrium position in the process of adsorption, ∆H =...
Which of the following process does not occur at the interface of phases?
(i) crystallisation (ii) heterogeneous catalysis (iii) homogeneous catalysis (iv) corrosion Correct Answer: (iii) homogeneous catalysis Explanation: The homogeneous catalysis do not occur in...