Environment for chemical reaction with reference

You can define new Reaction command; I also would suggest to use rxn acronym instead of rea for better code readability (rxn stands exclusively for "reaction", whereas "rea" has numerous meanings). Adapted from my answer:

\documentclass{article}
\usepackage{amsmath,}
\usepackage{chemmacros}
    \chemsetup{
        modules = {reactions},
        formula = mhchem,
        reactions/tag-open    = {(},
        reactions/tag-close   = {)},
    }
\usepackage{hyperref}
\newcommand{\rxnref}[1]{Reaction~\ref{#1}}

\begin{document}
You can see the chemical decomposition at \rxnref{rxn:bla} and its mathematical representation in \autoref{eq:foo}.

\begin{equation}\label{eq:foo}
    t^2 + 27t
\end{equation}

\begin{reaction}\label{rxn:bla}
    \ce{SiC + 2O2 -> CO2 + SiO2}
\end{reaction}

\end{document}

With the code of a previous answer of mine and some additions

\documentclass{article}
\usepackage{amsmath}
\usepackage{chemmacros}
\usepackage{hyperref}

\makeatletter % patchcmd from etoolbox, loaded by chemmacros
\patchcmd{\hyper@makecurrent}
 {\edef\Hy@param{#1}}
 {\xHy@param@def{#1}}
 {}{}
\def\xHy@param@def#1{%
  \edef\@tempa{\csname theH#1\endcsname}%
  \edef\@tempa{\expandafter\@car\@tempa\@nil}%
  \edef\Hy@param{\if R\@tempa reaction\else#1\fi}%
}
\makeatother
\newcommand\reactionautorefname{Reaction}

\chemsetup{
  modules = {reactions},
  formula = mhchem,
  reactions/tag-open=(R,
  reactions/tag-close=),
}

\begin{document}
You can see the chemical decomposition at \autoref{rea:bla} and its 
mathematical representation in \autoref{eq:foo}.
\begin{equation}\label{eq:foo}
t^2 + 27t
\end{equation}
and there is a reaction
\begin{reaction}\label{rea:bla}
\ce{SiC + 2O2 -> CO2 + SiO2},
\end{reaction}  

\end{document}