Q.Which is the most resistant alcohol towards oxidation reaction among the follwoing ?
A. $CH_3-CH_2-OH$
B. $(CH_3)_2CH-OH$
C. $(CH_3)_3C-OH$
D. $C_2H_5-\underset{CH_3}{\underset{|}{CH}}-OH$

Step 1. Classify each alcohol. A. CH3-CH2-OH is a primary (1 degree) alcohol. B. (CH3)2CH-OH is a secondary (2 degree) alcohol. C. (CH3)3C-OH is a tertiary (3 degree) alcohol -- its -OH-bearing carbon has three methyl groups and no hydrogen. D. C2H5-CH(CH3)-OH is also a secondary (2 degree) alcohol.

Step 2. Apply section 11.4.4's oxidation rule. Oxidation of an alcohol (with CrO3, PCC, KMnO4, etc.) works by removing the hydrogen that sits on the -OH-bearing carbon itself (alongside the O-H hydrogen) to form the C=O of an aldehyde or ketone. Primary alcohols (one such H) oxidise to aldehydes (then further to acids); secondary alcohols (one such H) oxidise to ketones. A tertiary alcohol's -OH-bearing carbon has NO hydrogen of its own to remove, so ordinary oxidation is structurally impossible; only fo …

Classifying each alcohol as primary/secondary/tertiary and applying section 11.4.4's rule that oxidation requires a hydrogen on th …

• Confusing 'resistant to oxidation' with 'unreactive overall' -- tertiary alcohols are perfectly reactive in other respects (e.g. fastest with HX in the Lucas test), they are specifically resistant to OXIDATION. …