Addition, substitution, elimination and esterification mechanisms
≈ 50 minAddition, substitution, elimination and esterification mechanisms
Reaction mechanisms at this level are chemical stories told by bonds and functional groups. Addition removes a C=C double bond and attaches new atoms; substitution exchanges an atom or group for another; elimination removes a small molecule and creates a double bond; esterification links an alcohol and carboxylic acid to form an ester plus water, usually with acid catalyst and heating. Compare reactant and product formulae to decide which atoms were added or removed. A balanced equation and named conditions make a proposed reaction testable. Do not use vague phrases such as 'the molecule changes' when the functional group can be shown.
Work it through
Ethanol can undergo elimination when heated with a suitable acid catalyst to form ethene and water. The alcohol loses H and OH overall as H₂O, and a C=C bond forms. The reaction is not addition because no atoms are added across an existing double bond. Drawing the before-and-after functional groups makes the classification clear.
Mastery target
Classify common organic reaction types from structural evidence, show a balanced product pattern and state relevant conditions or reagents.
Which reaction type forms ethene from ethanol by removing water?
Name the key chemistry term from Addition, substitution, elimination and esterification mechanisms that best fits the explanation and visual model.
What products form in esterification of an alcohol and a carboxylic acid?
Which statement corrects a common misunderstanding in Addition, substitution, elimination and esterification mechanisms?