Question 13.4: Classify the following alkene reactions as addition, elimina...
Classify the following alkene reactions as addition, elimination, or substitution reactions:
(a) CH _3 CH=CH _2+ H _2 \longrightarrow CH _3 CH _2 CH _3
(b) CH _3 CH _2 CH _2 OH \underset{\text{catalyst}}{\stackrel{H _2 SO _4}{\longrightarrow}}CH _3 CH=CH _2+ H _2 O
(c) CH _3 CH _2 Cl + KOH \longrightarrow CH _3 CH _2 OH + KCl
ANALYSiS Determine whether atoms have been added to the starting compound (addition), removed from the starting compound (elimination), or switched with another reactant (substitution).
(a) Two H atoms have been added in place of the double bond, so this is an addition reaction.
(b) A water molecule (H_2O) has been formed by removing an H atom and an —OH group from adjacent C atoms, forming a double bond in the process, so this is an elimination reaction.
(c) The reactants (CH_3CH_2Cl and KOH) have traded the —OH and the —Cl substituent groups, so this is a substitution reaction.