Tests for gases
Hydrogen, oxygen, carbon dioxide, ammonia and chlorine can be identified using different tests.
Hydrogen. A lighted wooden splint makes a popping sound in a test tube of hydrogen.
Oxygen. A glowing wooden splint relights in a test tube of oxygen.
A. I think sorry if it’s wrong
The polarity of a water molecule
comes from the uneven distribution of electron density of hydrogen and oxygen
atom. The oxygen in the water molecule is more electronegative than the
hydrogen. Water has a partial positive charge near the hydrogen atom and a
partial negative charge near the oxygen atom. The result of this
electrostatic attraction results in the bond called hydrogen bond. Also,
because of this bond, it has the ability to dissolve most of the solutes due to
its polarity and bonding.
Answer:
The required volume of hexane is 0.66245 Liters.
Explanation:
Volume of octane = v=1.0 L=
Density of octane= d = 
Mass of octane ,m= 
Moles of octane =
Mole percentage of Hexane = 45%
Mole percentage of octane = 100% - 45% = 55%

Total moles = 11.212 mol
Moles of hexane :

Moles of hexane = 5.0454 mol
Mass of 5.0454 moles of hexane,M = 5.0454 mol × 86 g/mol=433.9044 g
Density of the hexane,D = 
Volume of hexane = V

(1 cm^3= 0.001 L)
The required volume of hexane is 0.66245 Liters.