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Saturated fatty acids will contain ______ hydrogens than unsaturated fatty acids. Multiple choice question. fewer the same number of more

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jacob193

Answer:

If the two fatty acids contain an equal number of carbon atoms, the saturated fatty acid would contain more hydrogen atoms than the unsaturated one.

Explanation:

A fatty acid molecule is made up of two parts:

  • an aliphatic hydrocarbon chain (possibly very long,) and
  • a carboxyl group ([tex]-{\rm COOH}[/tex].)

The fatty acid is considered "saturated" if the hydrocarbon chain part contains only single carbon-carbon bonds. If the hydrocarbon chain of that fatty acid contains carbon-carbon double or triple bonds (such as [tex]-{\rm CH} = {\rm CH} - [/tex] and [tex]- {\rm C} \equiv {\rm C} -[/tex],) that fatty acid would be "unsaturated."

Each carbon atom typically needs four covalent bonds. For every additional carbon-carbon bond in the chain, one carbon-hydrogen bond would need to be deleted from both sides. Thus, adding one carbon-carbon bond would reduce the number of hydrogen atoms in the acid by two. For example:

  • [tex]- {\rm CH_{2} } - {\rm CH_{2}} -[/tex] (single bonds only) includes four hydrogen atoms.
  • An extra carbon-carbon bond would bring the number of hydrogen atoms down by two: [tex]-{\rm CH} = {\rm CH} - [/tex].
  • Another carbon-carbon bond would again bring that number by two more: [tex]- {\rm C} \equiv {\rm C} -[/tex].

Assume that the unsaturated fatty acid includes the same number of carbon atoms as the saturated fatty acid. The unsaturated fatty would include more carbon-carbon bonds, fewer carbon-hydrogen bonds, and therefore fewer hydrogen atoms overall.