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 type of reaction taking place is esterification, which is the process of forming an ester from an alcohol and a carboxylic acid.

1. The use of a water bath provides a controlled and even heating environment, preventing overheating which could lead to side reactions or decomposition of the reactants.
2. Since methanol is flammable, a water bath reduces the risk of fire hazards associated with direct heating.

The balanced equation for the reaction of methanol and propanoic acid to form propyl propanoate is:

Where the structural formula for propyl propanoate is:

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

The inorganic reactant in reaction 2 is typically represented as HBr, which is bromine in its hydrated form.

The IUPAC name for compound B, which forms after the first reaction, is 2-bromohexane.

The type of reaction represented by reaction 1 is an addition reaction where the haloalkane reacts with HBr to form an alkyl bromide.

The catalyst used in reaction 3 is typically a metal halide, such as zinc chloride (ZnCl₂).

The IUPAC name of compound D is hexane.

The type of reaction represented by reaction 3 is a substitution reaction, where one halogen is replaced by another group.

Compound A is a secondary haloalkane.