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Topic: Water Purification.

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Why is alum added to water?

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Because water does not like to be alone.

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It wants somebody's company.

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No.

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Alum is added to purify water.

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Alum is aluminium sulfate.

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It acts as a coagulant.

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A coagulant attracts and binds with extremely fine and small particles to form a large particle.

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I won't use it.

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But why?

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Because it will attract all small insects and make a large insect.

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You are just unbelievable.

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When a solution of alum is added to impure water.

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It attracts and binds with contaminants and fine suspended particles of mud, dirt, etc.

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To form large particles.

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Being large, these particles can be removed by filtration, or when they settle down due to gravity.

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They can be removed through decantation, giving us pure water.