Question

Oil floats on water. The most accurate reason for this is:
(A) Oil is less dense than water
(B) Oil is immiscible(does not dissolve) in water
(C) Oil is both less dense and immiscible with water
(D) Water is heavier than oil.

Answer 1

Hint: We know that oil and water both have different - different densities. And they both are immiscible. Water is polar and oil is nonpolar.

Complete step by step solution:
- We know that oil and water are of different densities. Water is more dense than oil. And Oil isn't heavier than water.
- Water molecules are only attracted to water molecules.
- When we added oil to the water they did not mix together. Instead the oil created a layer on the surface of the water.
- Water molecules are made up of one oxygen atom and two hydrogen atoms. Water molecules are polar. This polarity allows water molecules to form strong hydrogen bonds with each other. The charges at either end of the water molecule helps to attract other molecules.
- Oils are nonpolar, and they’re not attracted to the polarity of water molecules,
because oil is less dense than water, it will always float on top of water.
- Water molecules are made up of oxygen and hydrogen atoms bonded together. Oxygen is heavier and smaller than carbon, so a volume of water molecules is heavier than the same volume of oil molecules. This makes water more dense than oil.
So, the correct and most accurate option is “A”.

Note: Oils are hydrophobic, or “water fearing.” Instead of being attracted to water molecules, oil molecules are repelled by them.