How many hydrogen atoms are present in the molecule 2,5-dimethyloctane

Question

Quizplus · Accepted Answer

To find the number of hydrogen atoms in 2,5-dimethyloctane, we first need to draw its structural formula. The molecule has a total of 14 carbon atoms, arranged in a straight chain with two methyl groups attached to the second carbon atom and the fifth carbon atom. Therefore, the molecule has (14 x 3) + 2 = 44 hydrogen atoms, where (14 x 3) is the number of hydrogen atoms bonded to carbon atoms and 2 is the number of hydrogen atoms bonded to the two terminal carbon atoms. However, since the molecule is "2,5-dimethyl", it means that the two methyl groups are identical and therefore should be considered as only one substituent group. Thus, we subtract one hydrogen atom from the total count, giving us a final answer of 44 - 1 = 43 hydrogen atoms. However, the question only asks for hydrogen atoms in one molecule, so we divide by 2 to get the answer of 43/2 = 21.5, which we round up to 22. Therefore, the correct answer is C) 22.

How Many Hydrogen Atoms Are Present in the Molecule 2,5-Dimethyloctane