Question

Order the following hydrocarbons from lowest to highest boiling point:C₂H₆, C₃H₈ and C₄H₁₀,

Short answer

the order of boiling point from lowest to highest is,

\({{\rm{C}}_2}{{\rm{H}}_6} < {{\rm{C}}_3}{{\rm{H}}_8} < {{\rm{C}}_4}{{\rm{H}}_{10}}\)

Step-by-step solution

Define polarizability

A molecule with a charge cloud that is easily distorted is said to be very polarizable and will have large dispersion forces; one with a charge cloud that is difficult to distort is not very polarizable and will have small dispersion forces.

 Identify the name of the compound

The given compounds are,

\({{\rm{C}}_2}{{\rm{H}}_6},{{\rm{C}}_3}{{\rm{H}}_8}\), and\({{\rm{C}}_4}{{\rm{H}}_{10}}\).

The name of the compound\({{\rm{C}}_2}{{\rm{H}}_6}\)is Ethane.

The name of the compound\({{\rm{C}}_3}{{\rm{H}}_8}\)is propane.

The name of the compound\({{\rm{C}}_4}{{\rm{H}}_{10}}\)is butane.

\({{\rm{C}}_4}{{\rm{H}}_{10}},{{\rm{C}}_3}{{\rm{H}}_8}\)and\({{\rm{C}}_2}{{\rm{H}}_6}\)are non-polar compounds.

The intermolecular force present in these compounds is London dispersion forces.

Larger the molecule, the dispersion forces would be larger, and the boiling point would be higher.

Among the given compounds,\({{\rm{C}}_4}{{\rm{H}}_{10}}\)is a larger molecule so that the dispersion forces would be stronger in them and they will have the highest boiling point.

The order of boiling point of compounds is given as,

\({{\rm{C}}_2}{{\rm{H}}_6} < {{\rm{C}}_3}{{\rm{H}}_8} < {{\rm{C}}_4}{{\rm{H}}_{10}}\)

So, the order of boiling point from lowest to highest is,

\({{\rm{C}}_2}{{\rm{H}}_6} < {{\rm{C}}_3}{{\rm{H}}_8} < {{\rm{C}}_4}{{\rm{H}}_{10}}\).