Hard water boiling. When this is the case, it is usually caused by the presence of calcium sulphate/calcium chloride and/or magnesium sulphate/magnesium chloride in the water, which do not precipitate out as the temperature increases. Ions causing permanent hardness of water can be removed using a water softener, or ion exchange column. Total Permanent Hardness = Permanent Calcium Hardness + Permanent Magnesium Hardness With hard water, soap solutions form a white precipitate (soap scum) instead of producing lather, because the 2+ ions destroy the surfactant properties of the soap by forming a solid precipitate (the soap scum). A major component of such
Magnesium oxychloride at about 23 °C, the completely liquid region has vertices at the following triple equilibrium points (as mass fractions, not molar fractions): The other vertices are pure water, magnesium chloride hexahydrate, and the saturated solution (0.0044 MgO + 0.9956 by mass). The anhydrous forms decompose when heated above 450-500 °C by decomposition of the hydroxide and chloride anions, releasing water and hydrogen chloride and leaving a magnesium oxide residue, by the reactions: Extended exposure of magnesium oxychlorides to water leaches out the soluble , leaving hydrated brucite . On exposure to the atmosphere, the oxychlorides will slowly react with carbon