Advertisements
Advertisements
Question
Draw labelled diagram Dialysis.
Solution
APPEARS IN
RELATED QUESTIONS
Write one difference in Multimolecular colloid and Associated colloid
Define the following with a suitable example, of each:
Multimolecular colloid
Define the following with a suitable example, of each:
Gel
Explain Electrophoresis diagramatically.
Explain the term emulsion and types of emulsions.
Explain micelle formation in a soap solution.
Draw labelled diagram Tyndall effect.
Which one of the following methods is used to make platinum sol?
The order of coagulating power of following ions in the coagulation of a positive sol is:
i. \[\ce{PO^{3-}_4}\]
ii. \[\ce{SO^{2-}_4}\]
iii. \[\ce{[Fe(CN)6]^{4-}}\]
iv. \[\ce{NO^-_3}\]
Which of the following is NOT true for lyophilic colloids?
Tyndall effect is observed due to ____________.
Which of the following can form colloidal sol with water?
Which of the following is multimqlecular colloid?
Which of the following ionic species has highest precipitating power?
Some colloids are stable by their nature, i.e., gels, alloys, and solid foams. Gelatin and jellies are two common examples of a gel. The solid and liquid phases in a gel are interdispersed with both phases being continuous. In most systems, the major factor influencing the stability is the charge on the colloidal particles. If a particular ion is preferentially adsorbed on the surface of the particles, the particles in suspension will repel each other, thereby preventing the formation of aggregates that are larger than colloidal dimensions. The ion can be either positive or negative depending on the particular colloidal system, i.e., air bubbles accumulate negative ions, sulphur particles have a net negative charge in a sulphur sol, and the particles in a metal hydroxide sol are positively charged. Accumulation of charge on a surface is not an unusual phenomenon-dust is attracted to furniture surfaces by electrostatic forces. When salts are added to lyophobic colloidal systems the colloidal particles begin to form larger aggregates and a sediment forms as they settle. This phenomenon is called flocculation, and the suspension can be referred to as flocculated, or colloidally unstable. If the salt is removed, the suspension can usually be restored to its original state; this process is called deflocculation or peptization. The original and restored colloidal systems are called deflocculated, peptized, or stable sols.
Why does a small amount of salt have such a dramatic effect on the stability of a lyophobic colloidal system? The answer lies in an understanding of the attractive and repulsive forces that exist between colloidal particles. Van der Waals forces are responsible for the attractions, while the repulsive forces are due to the surface charge on the particles. In a stable colloid, the repulsive forces are of greater magnitude than the attractive forces. The magnitude of the electrical repulsion is diminished by addition of ionized salt, which allows the dispersed particles to aggregate and flocculate. River deltas provide an example of this behaviour. A delta is formed at the mouth of a river because the colloidal clay particles are flocculated when the freshwater mixes with the salt water of the ocean.
Settling down of colloidal particles to form a suspension is called ______.
Which of the following electrolytes will have maximum coagulating value for AgI/Ag+ solution?
A colloidal system having a solid substance as a dispersed phase and a liquid as a dispersion medium is classified as ______.
An emulsion cannot be broken by:
(i) heating
(ii) adding more amount of dispersion medium
(iii) freezing
(iv) adding emulsifying agent
Gelatin which is a peptide is added in icecreams. What can be its role?
Why are some medicines more effective in the colloidal form?
How does the precipitation of colloidal smoke take place in Cottrell precipitator?
Toluene is oxidised to benzoic acid by
The coagulation of 200 ML of position sol took place when 0.73 HCL was added to its without changing the volume much. The flocculation value of HCL for the colloid is.
For coagulating 200 ml of arsenious sulphide sol, 10 ml of 1 m NaCl solution is required find out the flocculation value of NaCl.
In which of the following, the Tyndall effect is not observed?
Which of the following is most powerful to coagulate the negative colloid?
Smoke is an example of ______.
Blood may be purified by ______.
Identify the correct decreasing order of precipitation power of flocculating ion added, from following.
