Question

rank the following molecules by increasing strength of dispersion force.
4 least --> 2 --> 3 --> 1 most
ch3ch2och3
ch3ch2ch3
ch3ch2ch2och2ch3
ch3ch2och2ch3

Explanation:

Dispersion forces (London dispersion forces) increase with the size (molar mass) and surface area of the molecule. Larger molecules have more electrons, which can create stronger temporary dipoles.

• \(CH_3CH_2CH_3\) (propane) is the smallest molecule among them, so it has the weakest dispersion forces.
• \(CH_3CH_2OCH_3\) (ethyl methyl ether) has a moderate size.
• \(CH_3CH_2OCH_2CH_3\) (diethyl ether) is larger than \(CH_3CH_2OCH_3\).
• \(CH_3CH_2CH_2OCH_2CH_3\) (butyl ethyl ether) is the largest molecule, so it has the strongest dispersion forces.

Answer:

\(CH_3CH_2CH_3\): \(4\)
\(CH_3CH_2OCH_3\): \(2\)
\(CH_3CH_2OCH_2CH_3\): \(3\)
\(CH_3CH_2CH_2OCH_2CH_3\): \(1\)