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Explain what is observed (i) when a beam of light is passed through a colloidal sol. (ii) an electrolyte, NaCl is added to hydrated ferric oxide sol. (iii) electric current is passed through a colloidal sol? |
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Answer» Solution :(i) SCATTERING of light by colloidal PARTICLES takes place and path of light becomes visible (Tyndall effect).(ii) The positively charged colloidal particles of `Fe(OH)_3`GET coagulated by the oppositely charged `CL^(-)`ions provided by NaCl. (iii) On passing electric current, the colloidal particles move TOWARDS the oppositely charged electrode where they lose their charge and get coagulated. This is electrophoresis process. |
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