In organic chemistry, adding a hydrogen is considered __ and removing a hydrogen is considered __.

In organic chemistry, adding a hydrogen atom to a molecule is characterized as a reducing process. This is because adding hydrogen typically involves the addition of electrons to the molecule, which decreases its oxidation state. In essence, reduction is defined by the gain of electrons or the decrease in oxidation state, and the addition of hydrogen aligns with this definition.

Conversely, removing a hydrogen atom from a molecule is classified as an oxidation process. This occurs because the removal of hydrogen effectively removes electrons (as each hydrogen atom carries one electron), which raises the oxidation state of the molecule. Oxidation is traditionally defined as the loss of electrons or an increase in oxidation state, so the removal of hydrogen supports this concept.

Therefore, the correct associations for the processes of adding and removing hydrogen in organic chemistry are effectively reducing and oxidizing, respectively. This understanding is fundamental in quantitative and qualitative analyses of reactions in organic chemistry.