Question

Write two points of difference between hard and soft water.

Answer 1

As we all know that water is generally a crystal clear, odourless and tasteless substance but it consists of minerals and chemicals as well and the presence of these minerals in water determines its hardness and softness. Water can exist in all three states including solid, liquid and gaseous states.

Complete step by step answer:
Water is composed of Hydrogen and Oxygen and can exist in all the three states including solid, liquid and gaseous. It is liquid at room temperature and it is odourless, nearly colourless and tasteless substance and provides no calories or any organic nutrients to the life forms.

Water consists of minerals like calcium and magnesium which are responsible for its hardness. These minerals are beneficial for health and add flavours to the hard water. Water hardness can be classified into two types: temporary hardness and permanent hardness. The temporary hardness is caused by the presence of calcium bicarbonates and magnesium bicarbonates and permanent hardness is caused by the presence of calcium sulphate or calcium chloride and magnesium sulphate or magnesium chloride. To reduce the temporary hardness water can be simply boiled or it can be treated with calcium hydroxide. When soap reacts with calcium in water, it results in the formation of soap scum.Soft water is the one that contains low ions concentrations especially low calcium and magnesium ion concentrations. Due to low calcium ions, there is no formation of soap scum. The natural source of soft water is rainwater.

Therefore, the key difference between soft water and hard water is:
a. The presence of calcium and magnesium content
b. Hardness and softness can be easily determined by the soap scum, if soap is effective then washing hands can be easy and water will be soft and if soap is ineffective the water will be hard.

Note:
Hard water leaves spots on the washed dishes when they are dried whereas soft water does not leave any spot. Hard water is sometimes preferred as drinking water as it contains minerals and a certain flavour and soft water is normally salty in taste.