Apr 7, 2014

$C {H}_{3} C O O H$ yields hydrogen ions as the only positive ion in an aqueous solution.

It is the only one with a $C O O H$ group at the end. $C O O H$ is a carboxylic acid and the H can easily leave as H+. The other compounds are alcohols (ending in $C {H}_{3} C {H}_{2} O H$ ethanol is A; Sucrose, a disaccharide is B, which only has OH groups; and C is the same as A).

The H in alcohols are not as good a leaving group as it is in a carboxylic acid. The ending carbon has a double bonded oxygen also attached to it in addition to an OH group, making the Oxygen attached to the hydrogen very electronegative (the electrons are sitting closer to the oxygen) and making it easier for the hydrogen to pop off as H+.