Lower aliphatic acids having 1 to 5 carbons are soluble in water but higher fatty acids having six or more than six carbon are insoluble in water but soluble in alcohol. Explain.

SOLUTION: Lower fatty acids dissolve because H of COOH group can farm hydrogen bond with water in two ways:

The alkyl group of these acids is nonpolar and hydrophobic and this effect predominates when alkyl group has more than five carbons, thereby diminishing the solubility of the acid. Alcohols are less polar than water hence higher members are soluble in alcohol.