Please answer the following questions . Thank you .
- What is the cause of peptization ?
- Why the sun looks red at the time of setting ? explain on the basis of colloidial properties .
Peptization : Peptization may be defined as the process of converting a precipitate into colloidal form by shaking it with dispersion medium in presence of small amount of electrolyte. The electrolyte used for this purpose is called as peptizing agent.
Cause of peptization: During peptization, the precipitate adsorbs one of the ion of the electrolyte on its surface. The adsorbed ion is generally common with those of the precipitate. This cause development of positive and negative charge on precipitates which ultimately break up into smaller particles having the dimensions of colloids.
Eg: When freshly precipitated Fe(OH)3 is shaken with aqueous solution of FeCl3 (peptizing agent) it adsorbs Fe3+ ions and thereby break up into small-sized particles of the type [Fe(OH)3]Fe3+.
Earth has an atmosphere. Aerosols of dust, smoke, mist, and fog are the most convenient colloids in the atmosphere. Sunset often have a orange or red colour. Sunlight is made up of different colour of light, each having a different wavelength. During a sunset, more red light is scattered because of the aerosols in the lower atmosphere. So, the scattering effect of the aerosols is magnified, causing more red light to be scattered than other colours of light.
Cause of peptization: During peptization, the precipitate adsorbs one of the ion of the electrolyte on its surface. The adsorbed ion is generally common with those of the precipitate. This cause development of positive and negative charge on precipitates which ultimately break up into smaller particles having the dimensions of colloids.
Eg: When freshly precipitated Fe(OH)3 is shaken with aqueous solution of FeCl3 (peptizing agent) it adsorbs Fe3+ ions and thereby break up into small-sized particles of the type [Fe(OH)3]Fe3+.
Earth has an atmosphere. Aerosols of dust, smoke, mist, and fog are the most convenient colloids in the atmosphere. Sunset often have a orange or red colour. Sunlight is made up of different colour of light, each having a different wavelength. During a sunset, more red light is scattered because of the aerosols in the lower atmosphere. So, the scattering effect of the aerosols is magnified, causing more red light to be scattered than other colours of light.