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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
Define the following term:
Zeta potential
Define the following terms: Associated colloids
Out of BaCl2 and KCl, which one is more effective in causing coagulation of a negatively charged colloidal Sol? Give reason.
Give reasons for the following observations: Leather gets hardened after tanning.
Explain what is observed when an electrolyte NaCl is added to hydrated ferric oxide sol.
Explain what is observed when an electric current is passed through a colloidal sol?
Explain the term Electrophoresis
Explain the terms Coagulation
Which of the following will show Tyndall effect?
What causes brownian motion in colloidal dispersion?
Why does leather get hardened after tanning?
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: Colloidal solutions do not show brownian motion.
Reason: Brownian motion is responsible for stability of sols.
What is common in aqua sols and solid aerosols? How do they differ?
Gold number is associated with:-
What is electrophoresis?
Why a negatively charged sol is obtained when AgNO3 solution is added to KI solution?
Lyophilic sols are more stable than lyophobic sols because ______.
