Tag: what floats - what sinks

In hard water, lather is very difficult to form, leather is not formed in hard water.

A temporary hard water can from lather with soap. The ${ Ca }^{ 2+ }/{ Mg }^{ 2+ }$ ions of water displace ${ Na }^{ + }$ or ${ K }^{ + }$ ions from this salts & form insoluble $Ca/Mg$ salts of fatty acids. 

Soft water is surface water that contains low  concentrations of ions and in particular is low in ions of calcium and magnesium. Soft water naturally occurs where rainfall and the drainage basin of rivers are formed of hard, impervious and calcium poor rocks.

Hard water is water that has high mineral content (in contrast with "soft water"). Hard water is formed when water percolates through deposits of limestone and chalk which are largely made up of calcium and magnesium carbonates. Hard drinking water may have moderate health benefits, but can pose serious problems in industrial settings, where water hardness is monitored to avoid costly breakdowns in boilers, cooling towers, and other equipment that handles water.

Permanent hardness is caused by the presence of sulfates of $Ca/Mg$. Which further increases the hardness on boiling because boiling removes only water in the form of vapour while none of its mineral content boil away-they remain in the vessel.

Hard water does not lather with but instead forms a gooey mass called scum. Hard water is formed when water percolates through deposits of limestone and chalk which are largely made up of calcium and magnesium carbonates.

Boiling hard water with washing soda removes permanent hardness which removes ${ Ca }^{ 2+ }$ or ${ Mg }^{ 2+ }$ ions in a precipitation reaction.

Hardness of water can be of two types temporary and permanent hardness. Temporary hard water contains only bicarbonates of magnesium and calcium. It can be removed by boiling. Such water on treating with soap lathers easily.

Hardness of water can be of two types temporary and permanent hardness. Temporary hard water contains only bicarbonates of magnesium and calcium. It can be removed by boiling. Permanent hard water contains chlorides and sulfates of calcium and magnesium. It can be removed by adding washing soda.

Soaps are not suitable when hard water is used. Detergents can be used with both hard and soft water. Detergents are more soluble in water than soaps. They also have a stronger cleansing action than soaps. Detergents don't need expensive vegetable oil for their preparation as they can be prepared from hydrocarbons of petroleum. They can be used in acidic solutions whereas soaps cannot be used (free fatty acids are precipitated).