4.1 In an experiment, a test tube containing methanol, propanoic acid and a catalyst is heated in a water bath - English General - NSC Physical Sciences - Question 4 - 2024 - Paper 2

The reaction taking place is an esterification or condensation reaction. This involves the formation of an ester through the reaction of an alcohol and a carboxylic acid.

1. The use of a water bath provides a controlled, even heating environment, which minimizes the risk of overheating the reactants and ensures a steady reaction.
2. Methanol, being flammable, requires careful heating to prevent vapors from igniting; a water bath reduces this risk by maintaining lower, safer temperatures.

The balanced equation for the esterification of propanoic acid with methanol in the presence of concentrated sulfuric acid is as follows:

    CH₃-CH₂-COOH + CH₃OH ⇌ CH₃-COO-CH₂-CH₃ + H₂O

Here, propanoic acid (CH₃-CH₂-COOH) reacts with methanol (CH₃OH) to produce propyl propanoate (CH₃-COO-CH₂-CH₃) and water (H₂O).

The IUPAC name of the organic product formed from this reaction is propyl propanoate.

The inorganic reactant in reaction 2 is hydrogen, represented as H₂.

The IUPAC name of compound B, which is formed from compound A through the reaction, is 2-bromohexane.

Reaction 1 is an elimination reaction where the haloalkane reacts to produce compound B.

The catalyst used in reaction 3 is sodium hydroxide, represented as NaOH.

The IUPAC name of compound D is hexan-1-ol.

The reaction represented by reaction 3 is a substitution reaction, where compound B is substituted to produce compound A.

Compound A is a secondary haloalkane.