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प्रश्न
Why do we add alum to purify water?
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उत्तर
River water carries negatively charged colloidal particles of clay and sand; alum \[\ce{(K2SO4Al2(SO4)3 24H2O)}\] is added to river water to coagulate the colloidal particles of clay and sand. Thus, alum helps to purify water.
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संबंधित प्रश्न
What is the reason for the stability of colloidal sols?
Define the following terms: Associated colloids
Give reasons for the following observations:
Brownian movement provides stability to the colloidal solution.
Out of MgCl2 and AlCl3, which one is more effective in causing coagulation of negatively charged sol and why?
Give reasons for the following observations: Leather gets hardened after tanning.
Explain what is observed when a beam of light is passed through a colloidal sol.
Explain the term Electrophoresis
Explain the terms Dialysis
What happens when persistent dialysis of a colloidal solution is carried out?
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Answer the following question.
Why are medicines more effective in the colloidal state?
A colloidal sol is prepared by the given method in the figure. What is the charge on hydrated ferric oxide colloidal particles formed in the test tube? How is the solution represented?
A colloidal sol is prepared by the given method in the figure. What is the charge on hydrated ferric oxide colloidal particles formed in the test tube? How is the sol represented?
Which of the following will show Tyndall effect?
Which phenomenon occurs when an electric field is applied to a colloidal solution and electrophoresis is prevented?
(i) Reverse osmosis takes place.
(ii) Electroosmosis takes place.
(iii) Dispersion medium begins to move.
(iv) Dispersion medium becomes stationary.
What is Gold number?
Which of the following is a correct statement?
The conditions given below are in the context of observing Tyndall effect in colloidal solutions:
- The diameter of the colloidal particles is comparable to the wavelength of light used.
- The diameter of the colloidal particles is much smaller than the wavelength of light used.
- The diameter of the colloidal particles is much larger than the wavelength of light used.
- The refractive indices of the dispersed phase and the dispersion medium are comparable.
- The dispersed phase has a very different refractive index from the dispersion medium.
Choose the most appropriate conditions from the options given below:
