# NEET Chemistry Surface Chemistry Questions Solved

BOARD

What happens in the following activities and why?

(i) An electrolyte is added to a hydrated ferric oxide sol in water.

(ii) A beam of light is passed through a colloidal solution.

(iii) An electric current is passed through a colloidal solution.

(i) When NaCl is added to hydrated ferric oxide solution, then coagulation

will take place. A negatively charged solution is obtained with absorption

of ${\mathrm{OH}}^{-}$ion.

(ii) When electric current is passed through a colloidal solution, the positively

charged particles move towards cathode while negatively charged particles

move towards anode where they lose their charge and get coagulated.

The phenomenon is known as Electrophoresis.

(iii) When a beam of strong light is passed  through a colloidal solution,

scattering of light occurs by colloidal particles and the path of light

becomes visible and the phenomenon is known as Tyndall effect.

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