Problem: Ethylene glycol (HOCH2CH2OH), the major substance in antifreeze, has a normal boiling point of 198 oC. By comparison, ethyl alcohol (CH3CH2OH) boils at 78 oC at atmospheric pressure. Ethylene glycol dimethyl ether (CH3OCH2CH2OCH3) has a normal boiling point of 83 oC, and ethyl methyl ether (CH3CH2OCH3) has a normal boiling point of 11 oC.What are the major factors responsible for the difference in boiling points of the two ethers?

FREE Expert Solution

We are asked to determine the major factors responsible for the difference in boiling points of the two ethers:

Recall:

Recall that there are several types of intermolecular forces (IMF):

1. Ion-dipole interaction – occurs between an ion and a polar covalent compound; strongest IMF

2. Hydrogen bonding – occurs in compounds where hydrogen is directly connected to an electronegative element such as N, O, or F; 2nd strongest IMF

3. Dipole-dipole interaction – occurs between two polar covalent compounds; 3rd strongest IMF

4. Dispersion forces – occurs in all compounds and is the primary IMF exhibited by nonpolar compounds; weakest IMF


View Complete Written Solution
Problem Details

Ethylene glycol (HOCH2CH2OH), the major substance in antifreeze, has a normal boiling point of 198 oC. By comparison, ethyl alcohol (CH3CH2OH) boils at 78 oC at atmospheric pressure. Ethylene glycol dimethyl ether (CH3OCH2CH2OCH3) has a normal boiling point of 83 oC, and ethyl methyl ether (CH3CH2OCH3) has a normal boiling point of 11 oC.

What are the major factors responsible for the difference in boiling points of the two ethers?

Frequently Asked Questions

What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Intermolecular Forces and Physical Properties concept. If you need more Intermolecular Forces and Physical Properties practice, you can also practice Intermolecular Forces and Physical Properties practice problems.