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The precipitation of colloidal solution, with the help of addition of excess of an electrolyte is known as flocculation or coagulation. The electrolyte is known as flocculating agent, and the power of an electrolyte to precipitate a colloidal solution is known as flocculating power.
What is coagulating power or flocculating power?
Hint: Flocculating value or the coagulating value is the amount of the electrolyte which is needed so that 1 litre of colloidal solution precipitates easily. The coagulating power or flocculating power is the reciprocal of coagulating value or flocculating value.
What is meant by coagulating power?
Answer: Coagulating power of an electrolyte is the minimum amount of electrolyte in millimoles that must be added to one litre of a colloidal solution to bring about its coagulation. Coagulation is caused by. (i) Electrophoresis, (ii) Mutual precipitation by mixing oppositely charged sols in proper proportion.
What is flocculating value?
Flocculation value is defined as the minimum concentration required of an electrolyte to cause the coagulation or flocculation of a solution. Flocculation value is inversely proportional to the coagulating power of the ion.
Which has minimum flocculating power?
The minimum concentration of an electrolyte required to cause coagulation of a sol is called its flocculation value. It is expressed in millimoles per litre. If the flocculation value of MgSO4 for standard As2S3 sol is 3.33.
How do you calculate flocculating power?
The minimum amount of an electrolyte required to cause precipitation of one litre of a colloidal solution is called coagulation value or flocculation value of the electrolyte for the sol. The reciprocal of coagulation value is regarded as the coagulating power.
Which has maximum flocculation power?
Lower the coagulation value, more efficient is the electrolyte in causing coagulation of sol. We can say coagulation value is inversely proportional flocculation value. having lowest charge will have minimum power and hence have maximum flocculation value. Thus, the correct option is C.
What is hardy Schulze rule?
> Hardy Schulze rule states that the amount of electrolyte required for the coagulation of a definite amount of a colloidal solution is dependent on the valency of the coagulating ion. Hardy and Schulze observed that greater the valency of the flocculating ion or coagulating ion, the greater is its power to coagulate.
What is Coagulative value?
The precipitation of colloidal solution through induced aggregation by the addition of suitable electrolyte is called coagulation or flocculation. The minimum concentration of an electrolyte required to cause coagulation is known as coagulating value of sol.It is usually expressed in terms of milli-moles per litre.
What is Tyndall effect?
Tyndall effect, also called Tyndall phenomenon, scattering of a beam of light by a medium containing small suspended particles—e.g., smoke or dust in a room, which makes visible a light beam entering a window. The effect is named for the 19th-century British physicist John Tyndall, who first studied it extensively.
Is soap a sol?
A sol is a combination of a solid that is evenly dispersed throughout a fluid. Since, in Soap dispersion medium is liquid and dispersed phase is gas. And after going through the classification of colloidal solution as written above, we can simply conclude that Soap is an example of Foam.
What is the difference between coagulation and flocculation?
Coagulation: Particles that aggregate with themselves e.g. by the influence of a change in pH. Flocculation: Particles that aggregate by the use of polymers that binds them together.
What is Peptization give an example?
Peptization is the method of producing stable colloids using an electrolyte to split up and distribute a precipitate into the colloids. Example: When the ferric chloride is added to the precipitate of ferric hydroxide, the hydroxide precipitate transfer to the sol by absorbing ferric ions.
Is AS2S3 positively charged?
Since, AS2S3 is a negatively charged sol, the ion bearing the highest positive charge, is more effective for its coagulation. Al3+ has the highest positive charge, ie, +3, so it is more effective for the coagulation of AS2S3 sol.
What is gold no in chemistry?
The Gold Number is the minimum weight (in milligrams) of a protective colloid required to prevent the coagulation of 10 ml of a standard hydro gold sol when 1 ml of a 10% sodium chloride solution is added to it. It was first used by Richard Adolf Zsigmondy.
Which ion has least flocculation value for a positive sol?
PO4−3.
What is flocculating ion?
Coagulation or precipitation:-it is a process of aggregating together the colloidal particle so as to change them into large sized particles which ultimately settles as a precipitate. The ion which is responsible for neutralization of charge on the colloidal particles is called the coagulating ion or Flocculating ion.
What is the Colour of gold sol?
The colour of finest gold sol is red. Increasing the size of particles of gold, it becomes purple, then colour becomes blue and finally the colour we observed for gold is golden yellow.
What is the correct effective coagulating order?
These ions are called coagulating ions or flocculating ions. (ii) Greater is the valency of coagulating or the flocculating greater is its power to bring about coagulations. The correct option is K3[Fe(CN)6].
Which ion has maximum flocculation value for a positive sol?
Fe(OH)3 is positively charged. Hence Cl- ions with minimum opposite charge will have maximum flocculation value (minimum cagulating power).
Is Congo Red sol a positively charged sol?
Based on the nature of the charge on the colloidal particles, colloidal solutions are classified as positively charged or negatively charged sols. Starch sol, metal sols like copper sol and gold sol, metal sulphide sols and acid dyes like Congo red, are examples of negatively charged sols.
Which of the following will have highest flocculating power for ferric hydroxide colloid?
According to the above stated rule, Cryolite$\left( {N{a_3}Al{F_6}} \right)$has the maximum coagulating power to coagulate a positive solution of ferric hydroxide because Cryolite has the highly charged opposite ion. So, the correct answer is Option A.
What is hardy Schulze rule Explain with examples?
The coagulating or flocculate capacity of an electrolyte increases with increase in charge is known as Hardy – Schulze law. Example 1: To coagulate a negative sol, the coagulating capacity of positive ion is Al+3 > Mg+2 > Na+ Example 2: To coagulate a positive sol the coagulating capacitor of negative ion.
Why are colloidal solutions Coloured?
Larger particles absorb the light of longer wavelength and therefore transmit light of shorter wavelength. The colour of a colloidal solution depends upon the size of colloidal particles present in it. Larger particles absorb the light of longer wavelength and therefore transmit light of shorter wavelength.
What is the cause of Peptization?
Cause of peptization:– As electrolyte is added to a freshly precipitated substance, the particles of the precipitate preferentially adsorbs one particular type of ions of the electrolyte. As a result they get dispersed due to electrostatic repulsions.
