45. Muddy water is treated with alum in purification process, it is termed as : A.Emulsification B.Absorption C.Adsorption D.Coagulation
Answer: Option D Solution: Natural and wastewater contain small particulates that are suspended in water forming a colloid. These particles carry the same charges, and repulsion prevents them from combining into larger particulates to settle. Historically, dirty water is cleaned by treating with alum, Al2(SO4)3.12 H2O, and lime, Ca(OH)2. The phenomenon is known as coagulation.
