Question

Nowadays, domestic water purifiers are using a technique called ________.
A. reverse osmosis
B. MO
C. osmosis
D. none of these

Answer 1

Hint: The purification of water involves removal of minerals from impure water. This helps in removal of calcium and magnesium salts along with germs.

Complete step by step answer:
Domestic water purifiers are very useful in removing the hardness of water. The soluble calcium and magnesium salts responsible for the hardness is removed by the process of reverse osmosis.
Reverse osmosis is the reverse process of osmosis. In the osmosis process the solute molecules move from a low concentration side to a high concentration side. The two solutions which contain different concentrations are separated by a semipermeable membrane so that they do not mix.
In reverse osmosis the solute molecules move from a side of high concentration to a side of low concentration. As a result the dissolved calcium and magnesium salts present in the high concentration side get removed from water molecules and produce pure water.
In household water purifiers the RO (reverse osmosis) based purifiers offer the most effective method for giving best quality of water. In the RO purifiers force is applied on the high concentration side to pass it through the semipermeable membrane to low concentration side. The RO purifier is coupled with UV, TDS controller and mineralizer to retain the essential nutrients while killing and removing unwanted and harmful impurities.

Therefore, the correct option is A .

Note: Several other techniques are also quite effective for giving better results of purification. Boiling technique is the simplest method employed for purification of water. Other techniques which include water chlorination, distillation, iodine addition, solar purification, clay vessel filtration, UV and desalination are also used and they offer effective ways of preparing purified water for use.