A compound (X) containing C, H and O does not react with sodium. It also does not reduce Tollens’ reagent. On heating with an excess of hydroiodic acid (HI), (X) gives only one organic product (Y). On hydrolysis, (Y) gives a new compound (Z), which can be converted back into (Y) by reaction with red phosphorus and iodine. On oxidation with potassium permanganate, (Z) gives a monocarboxylic acid whose molar mass is 60 g mol−1.
What is the IUPAC name of the carboxylic acid formed from (Z)?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Ethanoic acid
The passage gives the molar mass of the monocarboxylic acid formed when (Z) is oxidised with potassium permanganate: 60 g mol−1. A saturated monocarboxylic acid has the formula CnH2n+1COOH.
\( \displaystyle M=14n+1+12+32+1=14n+46 \)
\( \displaystyle 14n+46=60 \)
\( \displaystyle n=1 \)
The acid is \( \ce{CH3COOH} \), ethanoic acid, formed by oxidation of ethanol (Z):
\( \displaystyle \ce{CH3CH2OH + 2[O]} \xrightarrow{\ce{KMnO4}} \ce{CH3COOH + H2O} \)