Question

Question #24620

Answer 1

A hydrogen atom attatched to the first carbon atom in a functional group.

Explanation:

"The alpha carbon (Cα) in organic molecules refers to the first carbon atom that attaches to a functional group, such as a carbonyl." https://en.wikipedia.org/wiki/Alpha_and_beta_carbon

The next carbon atom that attaches is the beta carbon, and so on using Greek letters. An alpha hydrogen is a hydrogen atom that attaches itself to an alpha carbon. Following that logic, a beta hydrogen is one that attaches itself to a beta carbon, etc. Below are examples of where this may occur.

https://chem.libretexts.org/Reference/Organic_Chemistry_Glossary/Alpha_Hydrogen

I hope I helped!