Answer to Question #105825 in Organic Chemistry for Lana

Question

Consider the following organic compounds:

ethane C2H6 (CH3CH3)
ethanol C2H6O (CH3CH2OH)
ethanoic acid C2H4O2 (CH3COOH)
methoxymethane C2H6O (CH3OCH3)
octane C8H18
octan-1-ol C8H18O

Of the four compounds containing two carbons, which is the most soluble in water? Explain your reasoning using intermolecular forces in your answer.

3. Between ethanol and octan-1-ol: Which compound is more polar? Explain your answer using intermolecular forces in your answer.

4. Which class of organic compounds would be the most soluble in non-polar compounds? Explain your reasoning using intermolecular forces.

5. Explain why the boiling point of ethanol is different from the boiling point of octan-1-ol. Use intermolecular forces in your answer.

6. Compare the flashpoint of methane to octane, methanol to octan-1-ol, and methanoic acid and octanoic acid. Explain your rationale using intermolecular forces.

Answer 1

2) Ethanoic acid. It forms strong intermolecular bonds with water due to Van der Waals forces.

3) Ethanol. The longer n-alcohol is, the lower the polarity of -OH is.

4) Alkanes, because they are the least polar.

5) Ethanol is more polar, so the intermolecular forces in it are higher then in octanol, and so it is harder to break bonds between moecules and to evaporate

6) Methan < octane; methanol > octan-1-ol; methanoic acid > octanoic acid. The more polar molecule is, the higher it's flashpoint.