I have some chemical reaction equations which I want to reference in the subscript of an inline equation.
\begin{subequations}
\begin{align}
\cee{
\text{NO} +\text{O}_3 &-> \text{NO}_2 +\text{O}_2\label{eq:example1},\\
\text{NO} + \text{O}_3 &-> \text{NO}_2^* + \text{O}_2\label{eq:example2},
}
\end{align}
\end{subequations}
$k_{\ref{eq:example2}}$
I want to refer to eq:example 2 as the subscript for k, so if example2 was equation 1b, it would be equivalent to:
$k_{1b}$
But 1b obviously changing according to the equation numbering. Is there any way to do this, as putting \ref in the $$ symbols does not work.