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?
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?
(i) When a beam of light is passed through a colloidal
solution, then scattering of light is observed. This is known as the
Tyndall effect. This scattering of light illuminates the path of the
beam in the colloidal solution.
(ii) When NaCl is added to ferric oxide sol, it dissociates to
give Na+ and Cl- ions. Particles of ferric
oxide sol are positively charged. Thus, they get coagulated in the
presence of negatively charged Cl- ions.
(iii) The colloidal particles are charged and carry either a
positive or negative charge. The dispersion medium carries an equal
and opposite charge. This makes the whole system neutral. Under the
influence of an electric current, the colloidal particles move
towards the oppositely charged electrode. When they come in contact
with the electrode, they lose their charge and coagulate.
(i) When a beam of light is passed through a colloidal solution, then scattering of light is observed. This is known as the Tyndall effect. This scattering of light illuminates the path of the beam in the colloidal solution.
(ii) When NaCl is added to ferric oxide sol, it dissociates to give Na+ and Cl- ions. Particles of ferric oxide sol are positively charged. Thus, they get coagulated in the presence of negatively charged Cl- ions.
(iii) The colloidal particles are charged and carry either a positive or negative charge. The dispersion medium carries an equal and opposite charge. This makes the whole system neutral. Under the influence of an electric current, the colloidal particles move towards the oppositely charged electrode. When they come in contact with the electrode, they lose their charge and coagulate.
