Are the following pairs identical, enantiomers, diastereomers, or constitutional isomers? Sort these pairs into the proper categories.

A chemical reaction is described by achemical equation, an expression that gives the identities and quantities of the substances involved in a reaction. A chemical equation shows the starting compound(s)—the reactants—on the left and the final compound(s)—the products—on the right, separated by an arrow.