Question

1. List three metal ions that are typically found in hard water. 2. What anion is usually associated with hard water? 3. Explain the concept of ion exchange. 4. List three methods for softening water.

Answer 1

Calcum cat Magnesium Mg²+ Iron Feet Most common is calcium and Magnesium Carbonateian (co²-) is usually associated with water hardness. Ion exchange It is a reversible interchange of one type of Leon present in an insoluble solid with on semilav ion present in the solution the solid surrounding This is usually used for softening water purification of chemicals. 1) son exchange (men described above) Ca 2+ and Mg 24 replaced by Nat & kt 2 lime softening Uses addition of limewater for precipitating (02 as caco, and Mg2t as Mg COH) thus saftening the water 3) atstation Reverse Osmosis uses applied pressure gradient accross semi bermeable membrane to remove water molecules from hard water pores are large enough to let water melecules pass but not la 2+ or mgztions