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Why branched chain hydrocarbons have lower boiling points?

Why branched chain hydrocarbons have lower boiling points?

Branched alkanes normally exhibit lower boiling points than unbranched alkanes of the same carbon content. This occurs because of the greater van der Waals forces that exist between molecules of the unbranched alkanes. The strong repulsive forces counterbalance the weak van der Waals forces of attraction.

Why the boiling point of branched chain alkanes are lower than straight chain isomers?

Where you have isomers, the more branched the chain, the lower the boiling point tends to be. Van der Waals dispersion forces are smaller for shorter molecules and only operate over very short distances between one molecule and its neighbors.

Why do linear structures have higher boiling points?

A straight chain alkane will have a boiling point higher than a branched chain alkane because of the greater surface area in contact with other molecules. Branching makes molecules more compact thus reduces the surface area.

Why do longer chain hydrocarbons have higher boiling points?

Longer hydrocarbon molecules have a stronger intermolecular force. More energy is needed to move them apart so they have higher boiling points . This makes them less volatile and therefore less flammable .

Why do boiling points depend on structures?

Large molecules have more electrons and nuclei that create van der Waals attractive forces, so their compounds usually have higher boiling points than similar compounds made up of smaller molecules. The attractive forces between the latter group are generally greater.

How does branching affect boiling point?

Branching decreases the boiling point So the increase of surface area increases the ability of individual molecules to attract each other. Branching in molecules decreases the surface area thereby decreasing the attractive force between individual molecules. As a result, the boiling point decreases.

What effect does branching of alkane chain has on its boiling point?

As branches increases, the surface area of molecule decreases resulting in a small area of contact. As a result, the Van der Waals force also decreases which can overcome at a relatively lower temperature. Hence, the boiling point of an alkane chain decreases with an increase in branches.

Why do boiling points differ?

Different liquids have different boiling points depending on the strength of bonding between the particles and the mass of the particles. The heavier the particles in the liquid, and the stronger the bonding, the higher the boiling point will be.

Why do branched chain compounds have lower boiling points than straight chain compounds?

Consequently, the boiling points of the branched chain alkanes are less than the straight chain isomers. The above extract from my book, mentions clearly that branching makes the molecule more compact and thereby decreases the surface area.

Why does a branched alkane have a higher boiling point?

A straight chain alkane will have a boiling point higher than a branched chain alkane because of the greater surface area in contact with other molecules.

Why does boiling point decrease with degree of branching?

The boiling points of any series of isomeric organic compounds decrease with degree of branching, not just isomeric alcohols. This is due to the weaker Van der Waals dispersion forces between branched organic molecules compared to straight chain molecules. Van der Waals dispersion forces are proportional to the surface area of the molecule.

How are the boiling points of hydrocarbons determined?

BOILING POINTS AND STRUCTURES OF HYDROCARBONS The boiling points of organic compounds can give important clues to other physical properties and structural characteristics. A liquid boils when its vapor pressure is equal to the atmospheric pressure.