Mohan went to his ancestral village during the summer holidays t met his uncle (chacha ji) and his family. Mohan's uncle has a very big house in the village but they have no piped water supply. They draw water from a well near their house. One day Mohan took a bucket of water from the well and started washing his dirty clothes with soap given by his aunt. Mohan observed that the soap did not give lather with well water easily, only a curdy precipitate was formed making it difficult to wash the clothes properly. Mohan had brought a packet of some powder withhim from the city. So mohanused this powder to wash his clothes with well water without facing any difficulty. Mohan explained everything to hisuncle's family and advised them to stop using for washing clothes by suing well water and asked them to use the powder which he had for washing clothes with the same well water easily.
(a) What type of water is the wel water? Why?
(b) Why is soap not suitable for washing clothes with well water?
(c) What was the powder used by Mohan for washing clothes easily even with well water?
(d) Why is this powder for washing clothes suitable even with well water?
(e) What values are displayed by Mohan in this episode?

Explanation

(a) The well water is hard water. The hardness of well water is due to the presence of calcium and magneisum ions in it.
(b) Soap is not suitable for washing clothes with hard well water because of the following reasons:
(i) A lot of soap is waste in reaching with the calcium and magnesium ions present in hard water to form an insoluble curdy precipitate (called scum) before it can be used for the real purpose of washing clothes.
(ii) The scum (or curdy precipitate) formed by the action of soap on hard water sticks to the clothes being washed and interferes with the cleanising ability of additiona soap.
(iii) A lot of water is also wasted in using soap to wash clothes with hard water because the clothes being washed have to be rinsed many more times with water to remove the scum sticking to them.
(d) Detergent powder.
(d) Detergents are suitable for washing clothes even with hard water because they do not form insoluble calcium and magnesium salts with hard water. Unlike soap, a detergent can lather well even with hard well water.
(e) The values displayed by Mohan are (i) Awareness (that the well water is hard water ) (ii) Knowledge of the working of soap and detergents with hard water (iii) Application of knowledge to solve day-to-day problems and (iv) Helping nature.