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प्रश्न
Why does leather get hardened after tanning?
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उत्तर
Animal skin is colloidal, in nature and carries positive charge. Tannin is a negatively charged colloidal solution. When leather is soaked in tannin, mutual coagulation of the two takes place and leather gets hardened.
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संबंधित प्रश्न
What is the reason for the stability of colloidal sols?
Give reasons for the following observations: Leather gets hardened after tanning.
Explain the terms Dialysis
What happens when persistent dialysis of a colloidal solution is carried out?
What happens when an emulsion is centrifuged?
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?
Which of the following will show Tyndall effect?
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.
(iii) Any amount of dispersed liquid can be added to emulsion without destabilising it.
(iv) Brownian movement stabilises sols.
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.
Match the statement given in Column I with the phenomenon given in Column II.
| Column I | Column II |
| (i) Dispersion medium moves in an electric field | (a) Osmosis |
| (ii) Solvent molecules pass through semi permeable membrane towards solvent side |
(b) Electrophoresis |
| (iii) Movement of charged colloidal particles under the influence of applied electric potential towards oppositely charged electrodes |
(c) Electroosmosis |
| (iv) Solvent molecules pass through semi permeable membranes towards solution side |
(d) Reverse osmosis |
Give reason for the following:
Lyophilic colloidal solutions are more stable than lyophobic colloidal solutions.
Gold number of protective colloids A, Band Dare 0.50, 0.01 and 0.10 and 0.005. The correct order of their protecting power is
The important factor in the stabilization of a colloidal solution is ______
Define coagulation.
What is electrophoresis?
Define the following term:
Coagulation
Coagulation value of the electrolytes AlCl3 and NaCl for As2S3 sol are 0.093 and 52 respectively. The No. of times AlCl3 has greater coagulating power than NaCl is ______.
