Question

Why do calcium ions make water hard but sodium ions do not?
A) Calcium forms insoluble compound with stearate ion present in soap
B) Sodium forms insoluble compound with stearate ion present in soap
C) Calcium forms soluble compound with stearate ion present in soap
D) Both calcium and sodium forms insoluble compound with stearate ion present in soap

Answer 1

Water is an all-purpose solvent. It is a clear, colourless, odourless, and tasteless chemical compound. Water is divided into two categories. There are two types of water: hard water and soft water. There is no difference between these two sorts in terms of touch , sensation or look. The mineral composition of each determines the difference.

Complete answer:
Hard water is defined as water that contains measurable amounts of naturally occurring minerals such as magnesium and calcium. These minerals are advantageous to one's health. They enhance the flavour of hard water. Water that is soft is water that has been treated. Only cations remain, and sodium is one of them. It has a salty flavour to it.
The mineral composition of calcium and magnesium determines the hardness or softness of water:
There are less than 17 parts per million in soft water.
Water that is somewhat hard has a hardness of 17 to 60 parts per million.
Water that is moderately hard has a hardness of 60 to 120 parts per million.
The hardness of the water ranges from 120 to 180 parts per million.
Water with a hardness of more than 180 parts per million is considered very hard.
Soaps, such as sodium stearate, are sodium or potassium salts of higher fatty acids. Higher fatty acid salts such as sodium stearate and sodium and potassium salts are water soluble, while their magnesium and calcium salts are not. As a result, water becomes hard. Calcium with the stearate ion (soap anion) creates an insoluble combination, whereas sodium stearate is soluble.

Note:
Drinking hard water may provide some health benefits. In industrial settings, where water hardness is monitored to minimise costly breakdowns in boilers, cooling towers, and other water-handling equipment, it can cause serious issues. Hard water is typically indicated in household settings by a lack of froth when soap is agitated in water, as well as the production of limescale in kettles and water heaters. Water softening is widely utilised to lessen the negative impacts of hard water wherever it is a problem.