Compound N reacts with sodium metal to produce a gas that gives a 'pop' sound with a burning splint N also…

Step 1: Analyze the question We need to identify compound N from two tests:

1. It reacts with sodium metal to give a gas that "pops" with a burning splint.
2. It reacts with ethanoic acid to give a sweet-smelling liquid.

Step 2: Concepts

• A gas that burns with a "pop" sound is hydrogen. Compounds with an -OH group (alcohols, carboxylic acids, water) release hydrogen when they react with sodium.
• A sweet, fruity-smelling liquid is an ester. Esters form when an alcohol reacts with a carboxylic acid (esterification), usually with concentrated H₂SO₄ as a catalyst.

Step 3: Work through the options

• A. Alkanol (alcohol): Reacts with Na to give H₂: 2R-OH + 2Na → 2R-ONa + H₂. It also reacts with ethanoic acid to give an ester: CH₃COOH + R-OH → CH₃COOR + H₂O. Both tests fit.
• B. Alkanoate (a salt or ester): A salt would not react with sodium to give H₂, and it would not esterify with ethanoic acid.
• C. Alkane: Alkanes are unreactive toward sodium and do not form esters.
• D. Alkanoic acid: It reacts with Na to give H₂, but it does not form an ester with ethanoic acid. Two acids do not esterify with each other.

Step 4: Example 2C₂H₅OH + 2Na → 2C₂H₅ONa + H₂ (pops with a burning splint) CH₃COOH + C₂H₅OH ⇌ CH₃COOC₂H₅ + H₂O (ethyl ethanoate, sweet smelling)

Answer: A. Alkanol

Exam tip: Remember "Na + H₂ pop = has -OH" and "sweet smell = ester". If a compound gives both results with ethanoic acid, it is an alcohol (alkanol), because only an alcohol plus an acid gives an ester.