2**. > - C4 (CH₃, terminal methyl): 3 H + 1 C = -3 + 0 = **-3**. > > Note that C2 (the alcohol-bearing carbon) is at oxidation level 0 — same as an aldehyde! This is because the alcohol's OH is balanced by an extra H. Oxidation of 2-butanol to butan-2-one (a ketone) raises C2 to **+1** (oxidation st