Which of the following reagents can cause oxidation of an alcohol? 1. Hot concentrated H2SO4 2. Alkaline KMnO4 3. Acidified K2Cr207 4. Acidified KMnO4 Select the answer using the code given below.

Oxidation of alcohols involves the addition of oxygen or the removal of hydrogen to form aldehydes, ketones, or carboxylic acids. Alkaline potassium permanganate (KMnO4) and acidified potassium dichromate (K2Cr2O7) are well-established strong oxidizing agents used for this purpose [1]. Acidified KMnO4 is also a powerful oxidizing agent capable of converting primary alcohols to carboxylic acids and secondary alcohols to ketones. In contrast, hot concentrated sulfuric acid (H2SO4) primarily acts as a dehydrating agent rather than an oxidizing agent for alcohols; heating ethanol with concentrated H2SO4 at 443 K results in the formation of ethene through dehydration. Therefore, while reagents 2, 3, and 4 are standard oxidizing agents for alcohols, reagent 1 is characterized by its dehydrating properties in this context. Based on standard chemical principles, the reagents that cause oxidation are 2, 3, and 4.

Sources

1. [1] Science , class X (NCERT 2025 ed.) > Chapter 4: Carbon and its Compounds > Formation of coal and petroleum > p. 71