7. Give reasons for the following I

1. Alum is added to water in sedimentation tanks.

 

A chemical compound like potash alum is sometimes added to the water to slow downmergespeed up the sedimentation process. This process is called sterilisationfilteringloading. Potash alum particles react with suspended impurities and enable them to settle more quickly.

  

2. Water is a universal solvent.

 

 

Water is the only solvent that has the ability to dissolve more compounds than any other. It has the ability to dissolve solids, liquids and gasessolids and gasessolids and liquidsliquids and gases. Hence, water is also known as the universal solvent.