(i) Ethanoic acid to ethanamine (ii) p-toluidine to 2-bromo-4-methylaniline.(iii) methyl bromide to ethanamine

(i) Conversion of ethanoic acid to ethanamine:

The transformation from ethanoic acid (also known as acetic acid) to ethanamine (also known as ethylamine) involves two steps: esterification and reduction.

Step 1: Esterification
React ethanoic acid with an alcohol (e.g., methanol) in the presence of a strong acid catalyst (e.g., sulfuric acid) to form the corresponding ester. The reaction is shown below:

Ethanoic acid + Methanol → Methyl ethanoate (ester) + Water

Step 2: Reduction
Reduce the ester (methyl ethanoate) to the amine (ethylamine) using a reducing agent such as lithium aluminum hydride (LiAlH4) or sodium borohydride (NaBH4). The reaction is as follows:

Methyl ethanoate + Reducing agent → Ethylamine + Alcohol

The overall reaction can be summarized as:

Ethanoic acid + Methanol + Reducing agent → Ethylamine + Water + Alcohol

(ii) Conversion of p-toluidine to 2-bromo-4-methylaniline:

The transformation from p-toluidine to 2-bromo-4-methylaniline involves two steps: bromination and methylation.

Step 1: Bromination
Brominate the p-toluidine using a brominating agent, such as bromine (Br2) or N-bromosuccinimide (NBS), in the presence of a solvent (e.g., acetic acid). The reaction is shown below:

p-toluidine + Bromine → 2-bromo-4-toluidine

Step 2: Methylation
Methylate the brominated product (2-bromo-4-toluidine) using a methylating agent like dimethyl sulfate (DMS) or methyl iodide (CH3I) in the presence of a base (e.g., sodium hydroxide). The reaction is as follows:

2-bromo-4-toluidine + Methylating agent → 2-bromo-4-methylaniline

The overall reaction can be summarized as:

p-toluidine + Bromine + Methylating agent → 2-bromo-4-methylaniline

(iii) Conversion of methyl bromide to ethanamine:

The transformation from methyl bromide to ethanamine involves two steps: nucleophilic substitution and reduction.

Step 1: Nucleophilic Substitution
Treat methyl bromide with ammonia (NH3) or an amine (e.g., ethylamine) in an organic solvent (e.g., ethanol) to perform nucleophilic substitution. The reaction is as follows:

Methyl bromide + Ammonia (or ethanamine) → Methylamine (or ethylamine) + Bromide ion

Step 2: Reduction
Reduce the methylamine (or ethylamine) using a reducing agent such as lithium aluminum hydride (LiAlH4) or sodium borohydride (NaBH4). The reaction is shown below:

Methylamine (or ethylamine) + Reducing agent → Ethanamine (or ethylamine) + Alcohol

The overall reaction can be summarized as:

Methyl bromide + Ammonia (or ethanamine) + Reducing agent → Ethanamine (or ethylamine) + Bromide ion + Alcohol

It's important to note that the actual reactants, conditions, and reagents used may vary depending on the specific reaction conditions and the desired product. Always ensure that you have the proper safety precautions and knowledge before attempting any chemical reactions in a laboratory setting.