Alcohols and Hydrogen bonding

Alcohol Polarity and Hydrogen Bonding

• Alcohols, represented as R-OH, have a hydroxyl (-OH) group, making them polar molecules.
• The electronegative oxygen atom in the hydroxyl group (O-H) contributes to their polarity.

Hydrogen Bonding and Boiling Points

• Hydrogen bonding occurs between alcohol molecules due to the presence of the -OH group.
• This bonding leads to higher boiling points for alcohols compared to alkane molecules with similar molecular masses.

Example: Boiling Points

• Methanol (CH3OH, mass = 32) has a boiling point of 64.7 °C.
• Ethane (C2H6, mass = 30) has a significantly lower boiling point of -88.6 °C.

Alcohol's Compatibility with Water:

• Alcohols can mix with water because their hydroxyl (-OH) groups can form hydrogen bonds with water molecules.

Conclusion

• Alcohols, with their hydroxyl groups, exhibit polarity and the ability to engage in hydrogen bonding.
• Hydrogen bonding contributes to the higher boiling points of alcohols compared to non-polar compounds.
• This ability to form hydrogen bonds allows alcohol to mix readily with water.