How to label equation inside tabbing environment?

Question

I 've used tabbing environment instead of align* environment in order to align all equations inside all align environment together as suggested in that answer for another:

https://tex.stackexchange.com/questions/120104/collectively-aligning-multiple-align-environments

I've also used the command \tagthisline to number specified equations, and used the following code in the preamble as mentioned in the above answer:

newcommand{\tagthisaux}{\refstepcounter{equation}(\theequation)}                                                      
 \newcommand{\tagthisline}{\tagthisaux}                                                     

It gives a number for the equation, but i cant label it, whenever i use the command label, or putting the label key inside two curly braces {} beside the command \tagthisline{...} the referring code also appears beside the equation.

\documentclass[12pt]{article}
\usepackage{siunitx}
\usepackage{amsmath}
\usepackage{mathtools}
\usepackage{amssymb}
\newcommand{\tagthisaux}{\refstepcounter{equation}(\theequation)}                                                           
\newcommand{\tagthisline}{\tagthisaux}
\begin{document}                                                         
\begin{tabbing} \hspace{3cm} \= \hspace{3cm} \= \hspace{.5cm} \= \hspace{3cm} \=
        \kill
    \> \(Ra_L\) \> \(=\) \> \(Gr\cdot\Pr\)\\
    \>\(\)\> \(=\) \> \(\frac{g\beta\,\Delta TL_c^3}{\mathcal{V}^2}\cdot\,Pr\) \tagthisline{ral}  
      \end{tabbing}
\end{document}

Answer 1

Please see if this meets the requirement

\documentclass[reqno]{amsart}
\usepackage{amsmath, amssymb}
\newcommand{\tagthisaux}{%
\refstepcounter{equation}%
(\theequation)%
}
\newcommand{\tagthisline}{\`\tagthisaux} 
\begin{document}
\begin{align}
1+ 1 &= 2 & 2 &= 3- 1 
\end{align}
\begin{tabbing}
 $1+1 = 0$ \= $\Rightarrow$ \= $1 = -1$ \= since $F$ is of characteristic $2$ \tagthisline \\
 second row \>  \> more 
\end{tabbing}




    \begin{tabbing} \hspace{3cm} \= \hspace{3cm} \= \hspace{.5cm} \= \hspace{3cm} \=
        \kill
        \> \(Ra_L\) \> \(=\) \> \(Gr\cdot\Pr\)\\
        \>\(\)\> \(=\) \> \(\frac{g\beta\,\Delta TL_c^3}{\mathcal{V}^2}\cdot\,Pr\) \tagthisline\label{key}  
    \end{tabbing}

reference eqn~\ref{key}

\end{document}