How can we compare the cleansing power of soap in hard water and soft water?

The simplest way to determine if water is hard or soft is the lather/froth test. If the water is very soft, soap will tend to lather up easily when agitated, whereas with hard water it will not. Toothpaste will also not froth well in hard water.





Soap is less effective in hard water because its reacts to form the calcium or magnesium salt of the organic acid of the soap. These salts are insoluble and form grayish soap scum, but no cleansing lather.How can we compare the cleansing power of soap in hard water and soft water?
simple,


hard water has chemicals in it due to which the soap is unable to produce much lather, hence not cleaning properly whereas in soft water, there are no chemicals to oppos the cleanising power of soap, thus more lather is formed and the cleansing power increases and the object becomes much more cleaner.