{:(,"Column A",,,"Column B"),(A.,"Hard water","()",a.,"Reverse osmosis"),(B.,"Soft water","()",b.,"Rain water"),(C.,"Desalinated water","()",c.,"Presence of "Ca^(+2)andMg^(2+)),(D.,"Lake water","()",d.,"Scum formation"),(,,"()",e.,"Lather formation"):}

{:(,"Column A",,,"Column B"),(A.,"Hard water","()",a.,"Reverse osmosis

1.	{:(,"Column A",,,"Column B"),(A.,"Hard water","()",a.,"Reverse osmosis"),(B.,"Soft water","()",b.,"Rain water"),(C.,"Desalinated water","()",c.,"Presence of "Ca^(+2)andMg^(2+)),(D.,"Lake water","()",d.,"Scum formation"),(,,"()",e.,"Lather formation"):}
Answer» Solution :A - c, d Hard WATER contains `Ca^(+2)` and `Mg^(2+)` ions and form scum with SOAP. B - e Soft water forms lather with soap. C - a Reverse osmosis process is USED for desalination. D - b Rain water is the PUREST form of natural water stored in lakes.