See image — Alcohols Phenols and Ethers Chemistry Question

💡 Solution & Explanation

Concept: Ease of oxidation of alcohols follows the order: primary alcohol > secondary alcohol > tertiary alcohol. Phenols are oxidized but under harsh conditions, ethers are very resistant to oxidation, and tertiary alcohols are not oxidized under normal conditions (they would require C-C bond cleavage). Step 1: Identify the functional class of each option. (a) CH3-CHOH-CH3 is 2-propanol (isopropanol), a secondary alcohol. Secondary alcohols are oxidized readily to ketones by common oxidizing agents (e.g., K2Cr2O7, KMnO4, PCC). (b) The structure shown is a phenol (hydroxybenzene derivative). Phenols can be oxidized but require stronger or specific oxidizing agents; they are less straightforwardly oxidized compared to simple aliphatic secondary alcohols under typical conditions. (c) CH3-CH2-O-CH2-CH3 is diethyl ether. Ethers are generally resistant to oxidation under normal laboratory conditions. (d) The structure is a tertiary alcohol (1-methylcyclohexan-1-ol type: cyclohexane ring with both -CH3 and -OH on the same carbon). Tertiary alcohols cannot be oxidized without breaking C-C bonds, making them the most resistant to oxidation. Step 2: Rank the options. - Option (a): Secondary alcohol → easily oxidized to a ketone (propan-2-one) by mild/common oxidizing agents. - Option (b): Phenol → can be oxidized but not as readily as a secondary aliphatic alcohol by standard reagents. - Option (c): Ether → very resistant to oxidation. - Option (d): Tertiary alcohol → cannot be oxidized under normal conditions. Step 3: Among all four, the secondary alcohol (option a) is oxidized most easily because it has an alpha-hydrogen on the carbon bearing -OH and no bulky substitution preventing oxidant access, and it converts cleanly to a ketone. Why other options fail: - (b) Phenol requires specialized oxidants and is not oxidized as easily as a simple secondary alcohol. - (c) Ethers lack the easily abstractable alpha-OH hydrogen needed for typical oxidation pathways; they are oxidized only under vigorous conditions. - (d) Tertiary alcohols have no hydrogen on the carbinol carbon, so standard oxidation (which requires C-H cleavage at that carbon) cannot proceed. Therefore, the correct answer is A.