Question

the four compounds below have similar molar masses. rank the pure liquids of the four compounds in order of increasing boiling point (i.e. 1 = lowest boiling point and 4 = highest boiling point). 1 c(ch3)4 2 ch3ch2och2ch3 4 ch3ch2ch2ch2oh 3 ch3ch2ch2ch2ch3

Explanation:

Step1: Analyze intermolecular forces

Intermolecular forces affect boiling - point. The stronger the intermolecular forces, the higher the boiling - point.

Step2: Identify forces in $C(CH_3)_4$

$C(CH_3)_4$ (neopentane) is a non - polar molecule. It has only London dispersion forces.

Step3: Identify forces in $CH_3CH_2OCH_2CH_3$

$CH_3CH_2OCH_2CH_3$ (diethyl ether) is a polar molecule due to the presence of the oxygen atom. It has dipole - dipole forces in addition to London dispersion forces.

Step4: Identify forces in $CH_3CH_2CH_2CH_2OH$

$CH_3CH_2CH_2CH_2OH$ (1 - butanol) has hydrogen bonding (due to the $-OH$ group), in addition to dipole - dipole and London dispersion forces. Hydrogen bonding is a very strong intermolecular force.

Step5: Identify forces in $CH_3CH_2CH_2CH_2CH_3$

$CH_3CH_2CH_2CH_2CH_3$ (pentane) is a non - polar molecule and has only London dispersion forces. But its surface area is larger than that of $C(CH_3)_4$, so it has stronger London dispersion forces.

Since London dispersion forces are weaker than dipole - dipole forces, and hydrogen bonding is the strongest among these intermolecular forces:

1. $C(CH_3)_4$ has the weakest intermolecular forces (only London dispersion forces and relatively small surface area), so it has the lowest boiling - point (rank 1).
2. $CH_3CH_2OCH_2CH_3$ has dipole - dipole and London dispersion forces, so it has a higher boiling - point than $C(CH_3)_4$ (rank 2).
3. $CH_3CH_2CH_2CH_2CH_3$ has stronger London dispersion forces than $C(CH_3)_4$ due to its larger surface area, so it has a higher boiling - point than $CH_3CH_2OCH_2CH_3$ (rank 3).
4. $CH_3CH_2CH_2CH_2OH$ has hydrogen bonding, so it has the highest boiling - point (rank 4).

Answer:

1. $C(CH_3)_4$
2. $CH_3CH_2OCH_2CH_3$
3. $CH_3CH_2CH_2CH_2CH_3$
4. $CH_3CH_2CH_2CH_2OH$