Q.Write the IUPAC name of alcohol having molecular formula C4H10O which is resistant towards oxidation.

Step 1. Identify the alcohol isomers of C4H10O. The four-carbon monohydric alcohols with formula C4H10O are: n-butanol (butan-1-ol, primary), isobutyl alcohol (2-methylpropan-1-ol, primary), sec-butyl alcohol (butan-2-ol, secondary), and tert-butyl alcohol (2-methylpropan-2-ol, tertiary) -- exactly the four compounds tabulated together in Table 11.1 and compared for boiling point in Problem 11.3.

Step 2. Apply the resistant-to-oxidation clue (section 11.4.4, also MCQ (iv)). Only a TERTIARY alcohol, whose -OH-bearing carbon has no hydrogen of its own, structurally resists ordinary oxidation (no C-H is available on that carbon for an oxidant to remove in forming a C=O).

Step 3. Identify and name it. Among the four C4H10O isomers, only tert-butyl alcohol, (CH3)3C-OH, is tertiary. Its IUPAC name (built by the alkanol rule of section 11.3.1: parent propane, methyl substituent, -OH at C2, giving the compound its own systematic name) is 2-methylpropan-2-ol.

Listing the four C4H10O alcohol isomers (from Table 11.1) and applying section 11.4.4's rule that only a tertiary alcohol resists oxidation

• Naming the compound by its common name only (tert-butyl alcohol) when the question specifically asks for the IUPAC name.
• Confusing 'resistant to oxidation' with 'unreactive'; tert-butyl alcohol reacts readily in many other respects (e.g. fastest in the Lucas test), it is oxidation specifically that it resists.