Which one of the following alcohols can be oxidised under suitable conditions to give a corresponding carbonyl compound such as an aldehyde or ketone?

Introduction / Context:
Oxidation reactions of alcohols are a key topic in organic chemistry. Primary and secondary alcohols can usually be oxidised to aldehydes, ketones, or further to carboxylic acids, while tertiary alcohols are resistant to simple oxidation because they lack a hydrogen atom on the carbon bearing the hydroxyl group. Aromatic compounds like phenol behave differently. This question asks you to identify which given compound can be oxidised to a carbonyl compound under appropriate conditions, highlighting the difference between primary, secondary, tertiary, and phenolic structures.

Given Data / Assumptions:

• 2 methyl 2 hydroxy propane is a tertiary alcohol (common name tert butanol).
• 2 hydroxy propane is a secondary alcohol, also called isopropanol or propan 2 ol.
• o nitrophenol is an aromatic compound with nitro and hydroxyl groups on a benzene ring.
• Phenol is an aromatic compound with a hydroxyl group directly attached to a benzene ring.
• We are looking for an alcohol that can be oxidised to a simple carbonyl compound, such as a ketone.

Concept / Approach:
Primary alcohols are oxidised to aldehydes and then to carboxylic acids. Secondary alcohols are oxidised to ketones. Tertiary alcohols generally do not undergo oxidation to carbonyl compounds without breaking carbon carbon bonds because the carbon bearing the hydroxyl group does not have a hydrogen (no alpha hydrogen) to remove. Phenols and substituted phenols undergo different types of reactions such as electrophilic substitution and oxidative coupling rather than simple conversion to carbonyl compounds. Among the options, 2 hydroxy propane is a secondary alcohol and can be oxidised to propanone, a ketone.

Step-by-Step Solution:
Step 1: Identify the structure of 2 hydroxy propane. It has three carbon atoms and the hydroxyl group on the middle carbon, so it is a secondary alcohol. Step 2: Recall that secondary alcohols can be oxidised to ketones using oxidising agents such as acidified potassium dichromate or potassium permanganate. Step 3: Write the oxidation product of 2 hydroxy propane, which is propanone, a carbonyl compound (a ketone). Step 4: Recognise that 2 methyl 2 hydroxy propane is a tertiary alcohol where the carbon bearing the OH group has no hydrogen, so simple oxidation to a carbonyl compound is not possible without breaking the carbon skeleton. Step 5: Note that phenol and o nitrophenol are aromatic compounds, and their oxidation does not give simple aldehydes or ketones by straightforward mild oxidation; instead they undergo more complex reactions.

Verification / Alternative check:
In laboratory practice, when a secondary alcohol such as isopropanol is treated with an oxidising agent, it converts to a ketone such as acetone. This is a standard textbook example. In contrast, tertiary alcohols resist oxidation and may require very harsh conditions that break carbon carbon bonds, leading to fragmentation rather than a neat carbonyl compound. Phenol can be oxidised to quinones or other aromatic products, but that is not the same as the simple carbonyl formation described for aliphatic primary and secondary alcohols. Therefore, 2 hydroxy propane is the only option that fits the statement in the question.

Why Other Options Are Wrong:
2 methyl 2 hydroxy propane is a tertiary alcohol, and the carbon bearing the OH group has no hydrogen. Mild oxidants cannot convert it to a carbonyl compound without breaking the carbon skeleton, so it does not fit the requirement. o nitrophenol has a hydroxyl group on an aromatic ring and an ortho nitro substituent; its oxidation leads to aromatic products rather than a single simple carbonyl compound. Phenol is similar in that it is not converted to aldehydes or ketones under standard mild oxidation conditions but tends to form complex oxidation products such as quinones. These options therefore do not match the description given in the question.

Common Pitfalls:
A frequent error is to assume that any compound with an OH group is an alcohol that behaves the same way in oxidation reactions. Students may forget the important difference between aliphatic and aromatic hydroxyl compounds and between primary, secondary, and tertiary alcohols. Another mistake is misidentifying 2 hydroxy propane as a primary alcohol due to its simple name. To avoid these pitfalls, always consider the position of the OH group and the type of carbon it is attached to. Secondary alcohols like 2 hydroxy propane are oxidised to ketones, which are carbonyl compounds.

Final Answer:
The compound that can be oxidised to a corresponding carbonyl compound is 2 hydroxy propane (a secondary alcohol, isopropanol).