Tag: structure and properties of water

Water acts as a powerful ionizing agent due to its high dielectric constant. Water has high polarity and forms hydrogen bonds.

Water is cooled from $4^{\circ}C$ to $0^{\circ}C$. It is called "Anomalous expansion of water", i.e. The expansion between 4 and 0 is due to the formation of larger clusters in the water molecules.
When water molecules go from $4^{\circ}C$ to $0^{\circ}C$, they are forming groups in small lattices, what increases volume and decreases density. When water ices, then all their molecules are forming that lattice, as mineral crystals do, with the volume expanded.
Above $4^{\circ}C$, thermal expansion sets as thermal vibrations of the OH bonds of water becomes more vigorous, tending to shove the molecules farther apart and water expands.
As a result of this water at $4^{\circ}C$ is denser than that at $0^{\circ}C$. This causes floating of ice on water during winter. Bursting of pipes is also due to anomalous expansion.
Thus, Option B is correct.

Water boils at 100$^o$ while paper burns at 200$^o$. Thus water can be boiled in paper.

Water is not a mixture but a compound. It has elements hydrogen and oxygen which are combined chemically with two hydrogen and one oxygen atoms. These cannot be separated by any physical means.

Pure water is a bad conductor of electricity. This is because free electrons are not present in pure water which allow the flow of electricity. Pure water is a bad conductor of electricity.

Water in pure form is a bad conductor of electricity because of the absence of free electrons (salts and minerals) that allow the flow of electricity.

Salt and sugar are soluble in water and form solution with water. Oxygen is also water soluble because the aquatic animals are able to breathe because oxygen is present in the dissolved form. As temperature increases solubility decreases, that's why in Eutrophication there is high BOD.(Biological Oxygen Demand)

When we heat water, we can find bubbles coming from it. This is because the solubility of gases decreases as the temperature increases and that is why the dissolved air bubbles go out from the water. Then as the boiling point of the water is reached ($100^{\circ}C$), water vapour starts to form inside the liquid in the form of bubbles.  

Pure water is bad conductor of electricity due to lack of impurities (salts and minerals).