chemistry-hydrocarbons-alkanes-solubility of ethane

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We often say that "Like dissolves like". Both ethane and carbon tetrachloride are symmetrical molecules. Dispersion forces only exist between the molecules of ethane and CCl₄ . Both molecules can disrupt each others weak intermolecular bonding and mix together.

Ethanol has hydrogen bonding acting between its molecules. This type of bonding, although weak, is stronger than dispersion forces that act between the molecules of ethane. Ethanol is an assymetrical, polar molecule while ethane is a symmetrical non-polar molecule. So, when ethanol dissolves, hydrogen bonds between water molecules are broken, as are the hydrogen bonds between the molecules of ethanol and are reformed between the molecules of water and ethanol.

Ammonia also has hydrogen bonding acting between its molecules and as such is extremely soluble in water.

Hydrocarbons Solubility of ethane

Ethane is a symmetrical molecule. Weak forces of attraction, known as dispersion forces, exist between the molecules of ethane. The forces of attraction between ethane and water are not strong enough to overcome the hydrogen bonding that exists between the water molecules. Watch the animation on the right. Notice how the ethane molecules will group together. This minimises the surface area exposed to water. This formation has a lower energy state.
Explain why ethane is likely to dissolve in carbon tetrachloride (CCl₄). Explain why ethanol(CH₃CH₂OH), at room temperature, is a soluble liquid while ethane is an insoluble gas. Why is ammonia(NH₃) highly soluble in water? Would you expect salt to dissolve in ammonia as it does in water? Solution