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.
1. Which one of the following organic compounds has fruity smell?
3. The outermost layer of Earth is called _______.
4. Persons working in cement plants and lime stone quarries are prone to disease like
5. A polymeric substance used to make parachute is
6. Aromatic hydrocarbons contain at least _____ benzene like ring in their molecules.
7. Atomic number of which of the following elements is greater than that of Aluminium?
8. Rock salt is a mineral containing
9. The use of heat treatment of ore that includes smelting and roasting is termed:
10. The compound that has the least value for octane number is :