Advertisements
Advertisements
Question
Give reasons for the following observations: Leather gets hardened after tanning.
Advertisements
Solution
Animal skin (hide) is colloidal in nature and has positively charged particles, whereas tanning consists of negatively charged colloidal particles. When a hide is soaked in tanning, mutual coagulation takes place and as a result, leather gets hardened.
APPEARS IN
RELATED QUESTIONS
Define the following term:
Zeta potential
Define the following terms: Associated colloids
Out of MgCl2 and AlCl3, which one is more effective in causing coagulation of negatively charged sol and why?
Explain what is observed when an electric current is passed through a colloidal sol?
Which of the following will show Tyndall effect?
How does it become possible to cause artificial rain by spraying silver iodide on the clouds?
Why do we add alum to purify water?
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 |
Assertion: Coagulation power of Al3+ is more than Na+.
Reason: Greater the valency of the flocculating ion added, greater is its power to cause precipitation (Hardy Schulze rule).
Which of the following is a correct statement?
