Describe ion exchange resin method for softening hard water.

Describe permutit process for softening hard water.

Name the sodium compound which is used for softening hard water.

Fill in the blanks: The sodium compound used for softening hard water is _________

RH_2 (ion exchange resin) can replace Ca^(2+) ions in hard water as RH_2+Ca^(2+)rarr RCa+2H^+ . If 1 L of hard water after passing through RH_2 has pH=3 then hardness in parts per million of Ca^(2+) is :

Describe the various methods of birh control.

Describe biological method of pest control.