Uses of water

• domestic: drinking, cooking, washing, farming etc.
• industry: irrigation, cleaning &purification, as solvent, dyeing, bleaching process, hydropower stations

Test for water

• Cobalt(ii) chloride paper, paper turns from blue to pink to pink

Water purification

• Water from rain and river downstream is collected in reservoir
• water is transported via a pipe to a flocculation tank where alum, Al₂(SO₂)., and lime, Ca(OH)₂ are added to water so that small solid clay particles join together into large lumps of solid (coagulation)
• Water is moved to sedimentation tank where the lumps of solid settles to the bottom of the tank. This is called Sedimentation. Carbon, in form of activated charcoal, is added to remove the taste and smell of water
• Water is filtered off in filtration tank, where there are sand particles filter which traps the remaining solid particles in water
• Chorine and Florine are added in chlorination tank, chlorination. Chlorine is used to kill bacteria while fluorine is used to strengthen teeth.