Question

Which forces are intramolecular and which intermolecular?

(a) Those preventing oil from evaporating at room temperature

(b) Those preventing butter from melting in a refrigerator

(c) Those allowing the silver to tarnish

(d) Those preventing${\mathbf{O}}_{\mathbf{2}}$ in the air from forming O atoms

Short answer

1. Intermolecular forces prevent oil from evaporating at normal temperature.
2. Intermolecular forces are what prevent the butter from melting in the refrigerator.
3. Intramolecular forces are responsible for the tarnishing of silver.
4. Intramolecular forces are what prevent ${\mathbf{O}}_{\mathbf{2}}$ in air from generating O atoms.

Step-by-step solution

Oil

Oil is a non-polar chemical substance that contains primarily hydrocarbons and is hydrophobic/ lipophilic in nature.

Evaporation

The London dispersion forces present between the molecules, the process

of evaporation at room temperature is prevented.

London dispersive forces

In a refrigerator, the temperature of the system is too low to overcome the London dispersion attractive forces in the fat globules (present in butter).

Attractive nature

These forces are attractive in nature and are present between different molecules of butter.

Silver Tarnishing

Silver Tarnishing is a chemical process in which silver metal when exposed to the sulfur oxide vapors forms silver sulfide which converts white silver to black silver sulfide.

Intramolecular force

The silver atom reacts with the sulfur vapors to form silver sulfide. This is an intramolecular process where an atom is reacted.

Covalent bond

The force that prevent ${\mathbf{O}}_{\mathbf{2}}$ from forming O atoms is the strong covalent bond between the O atoms.

Intramolecular interactions

The covalent bond is always intramolecular in nature.