Questions

The two main components of air are nitrogen and oxygen. They are seperated by the fractional distillation of liquid air. Liquefied air contains liquid nitrogen and liquid oxygen. Liquid nitrogen with the lower boiling point more readily evaporates than the less volatile liquid oxygen. 

Most operating systems store files on a hard disk.

Venus is the only planet that rotates in clockwise where all other planets in the solar system rotates in anti - clockwise direction.

In this chemical reaction chlorine change oxidation number from 0 to -1 (reduction) and bromine change oxidation number from -1 to 0 (oxidation).

Chlorine is stronger oxidation reagent than bromine.

In VIIA or group 17 (halogen elements) there are six elements: fluorine (F), chlorine (Cl), bromine (Br), iodine (I), astatine (At) and tennessin(Ts).

They have high electronegativity because they have seven valence electrons in their outermost energy level, so they can gain an electron to have the octet rule.  

Going down in the group, element are weaker oxidazing reagent and less reactive.

Yeast used in making bread is a Fungus.

The Peloponnesian war, between Athens and Sparta from 431 to 404 BC ended in the defeat of Athens and the destruction of her democracy. Athens became a subject state of sparta. This war marked the beginning of the end of the "Glory that was Greece".