Which of the following electrolytes is least effective in coagulating ferric hydroxide solution?
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Solution
Smaller the charge on anion, lesser will be its coagulating power.
∴ KBr have Br– with least charge of – 1 on Br thus KBr is least effective in coagulating Fe(OH)3.
Gold number is the index for :
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Solution
Gold number is measure of protective power of lyophilic colloid.
Protective power of \(Colloid \propto \frac{1}{Gold Number}\)
The formation of micelles takes place only above
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Solution
The formation of micelles takes place only above a particular temperature called kraft temperature (TK)
The ability of an ion to bring about coagulation of a given colloid depends upon
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Solution
According to the Hardy schulze rule the coagulating effect of an ion on dispersed phase of opposite charge increases with the valency of the ion. Therefore more the charge on oppositely charged ion higher is the coagulation value.
Which of the following is most effective in causing the coagulation of ferric hydroxide sol?
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Solution
Fe(OH)3 is positive sol.K3[Fe(CN)6] will provide[Fe(CN)6]3– for coagulation having highest magnitude of –ve charge among given options.
The simplest way to check whether a system is colloidal or not is by
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Solution
Tyndall effect is the simplest way to check colloidal system since path of light beam becomes visible due to scattering of light.
In coagulating the colloidal solution of As2S3 which has the minimum coagulating value ?
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Solution
As2S3 is negative sol.For coagulating negative sol Al3+ is most effective. It is because higher the magnitude of the charge, the lower is coagulating value.
Adsorption is accompanied by
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Solution
Adsorption is an exothermic process i.e. ∆H of adsorption is always negative. When a gas is adsorbed,the freedom of movement of its molecules becomes restricted i.e.∆S is negative. Hence adsorption accompanied by decrease in enthalpy as well as decrease in entropy of the system.
When a strong beam of light is passed through a colloidal solution, the light will
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Solution
It is due to Tyndall effect.
Which of the following is a lyophilic colloid ?
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Solution
Gum is lyophilic colloid.