Compound X reacted with hot copper(II) oxide and the resulting product did not give a colour change when heated with Fehling's solution - Scottish Highers Chemistry - Question 8 - 2019

To identify Compound X, we need to consider the reactions involved. When alcohols are oxidized, primary and secondary alcohols can form aldehydes or ketones, which can react with Fehling's solution, causing a color change (the formation of a red precipitate).

1. Pentan-1-ol (A): This is a primary alcohol and would typically oxidize to pentanal, a compound that reacts with Fehling's solution, causing a color change.

2. Pentan-2-ol (B): This is a secondary alcohol. Upon oxidation with hot copper(II) oxide, it would convert to pentan-2-one, which does not react with Fehling's solution, resulting in no color change. Therefore, this is a possible candidate for Compound X.

3. Pentan-3-one (C): This is a ketone and, like other ketones, it does not oxidize or react with Fehling's solution, so it would also show no color change. However, it cannot be the starting material (Compound X) since it is not an alcohol.

4. Pentanoic acid (D): This is a carboxylic acid and does not produce a color change when heated with Fehling's solution either, but it is not an alcohol to begin with.

Based on this reasoning, pentan-2-ol (B) is the correct answer, as it does not cause a color change when treated with Fehling's solution after oxidation.