Isononanoic acid, also known as pelargonic acid, is a nine-carbon saturated fatty acid with the chemical formula C9H18O2. It contains a carboxylic acid functional group (COOH) and a linear hydrocarbon chain.
To determine the positions of the 18 hydrogen atoms in isononanoic acid, we need to examine the structure of the molecule. Since it is a straight-chain fatty acid, we can start by counting the hydrogen atoms on the carbon chain.
The carbon chain of isononanoic acid consists of nine carbon atoms (C9), which means there will be 2n+2 hydrogen atoms, where n is the number of carbon atoms. In this case, there will be (2 x 9) + 2 = 20 hydrogen atoms on the carbon chain.
However, isononanoic acid also contains a carboxylic acid group (COOH), which contributes two additional hydrogen atoms. Therefore, we need to subtract two from the total number of hydrogen atoms on the carbon chain.
20 - 2 = 18 hydrogen atoms
So, there are 18 hydrogen atoms in isononanoic acid. They are attached to the carbon atoms in the carbon chain, excluding the carbon atom in the carboxylic acid group (COOH).