Which of the following statements relating to carbon and its compounds are correct? 1. 1-Propyne has three double bonds. 2. The boiling point of acetic acid is higher than methane. 3. Ethanol reacts with sodium metal and produces hydrogen gas. 4. Esters give effervescence on reaction with sodium bicarbonate. Select the answer using the code given below.

Statement 1 is incorrect because 1-propyne is an alkyne, meaning it contains a triple bond between two carbon atoms, not three double bonds [3]. Statement 2 is correct; acetic acid has a boiling point of 391 K, which is significantly higher than methane's boiling point of 111 K due to stronger intermolecular forces like hydrogen bonding [1]. Statement 3 is correct as alcohols like ethanol react with sodium metal to produce sodium ethoxide and evolve hydrogen gas. Statement 4 is incorrect because while carboxylic acids react with sodium bicarbonate to produce effervescence (CO2 gas), esters generally do not react with sodium bicarbonate to produce effervescence under standard conditions. Therefore, only statements 2 and 3 are correct.

Sources

1. [3] Science , class X (NCERT 2025 ed.) > Chapter 4: Carbon and its Compounds > 2Na + 2CH3CH2OH → 2CH3CH2O–Na+ + H2 (Sodium ethoxide) > p. 72
2. [1] Science , class X (NCERT 2025 ed.) > Chapter 4: Carbon and its Compounds > 4.1 BONDING IN CARBON – THE COVALENT BOND > p. 59