To determine the structural formula of the carboxylic acid, we first need to find its molecular formula based on its molecular weight. The molecular weight of a carboxylic acid can be represented as:Molecular weight = 12n + 32 + 2n + 16 + 1where n is the number of carbon atoms in the carboxylic acid.Given the molecular weight of 118 g/mol, we can set up the equation:118 = 12n + 32 + 2n + 16 + 1Simplifying the equation:118 = 14n + 49Subtracting 49 from both sides:69 = 14nDividing by 14:n 4.93Since the number of carbon atoms must be a whole number, we can round n to 5.Now that we know there are 5 carbon atoms in the carboxylic acid, we can determine its molecular formula:C5H 25 +2O2C5H12O2The structural formula of the carboxylic acid is:CH3 CH2 3COOHThis carboxylic acid is called pentanoic acid or valeric acid. When it reacts with an alcohol in the presence of an acid catalyst, it forms an ester with a fruity smell.