Hard water: Difference between revisions

The permanent hardness of water is determined by the water's [[concentration]] of [[multivalent]] [[cations]] inwith thecharges water.greater Multivalentthan cationsor areequal positivelyto charged [[metal complex]]es with a charge greater than 12+. Usually, the cations have the charge of 2+, i.e., they are [[divalent]]. Common cations found in hard water include Ca²⁺ and Mg²⁺., Thesewhich ionsfrequently enter a water supplysupplies by leaching from minerals within an [[aquiferaquifers]]. Common [[calcium]]-containing minerals are [[calcite]] and [[gypsum]]. A common [[magnesium]] mineral is [[dolomite (mineral)|dolomite]] (which also contains calcium). [[Rain|Rainwater]] and [[distillation|distilled]] water are [[soft water|soft]], because they contain few of these [[ion]]s.<ref name=Ullmann>{{cite book|title=Ullmann's Encyclopedia of Industrial Chemistry - Water|last1=Weingärtner|first1=Herman]|date=December 2006|publisher= Wiley–VCH|location= Weinheim|doi=10.1002/14356007.a28_001}}</ref>