I'd state your problem counts of two parts. First, the counter, which is solved by adding to the preamble:
Next, the command delimiting the reaction.
The following defines the special environment directives, that takes an optional argument (key=value with the keys start and max, with start specifying the first directives index and max defining the ...
This use case is described in the perpage package manual on the first page:
will start footnote numbers with 2 on each page (the optional argument defaults to 1). 2 might be ...
The simplest way is to use \tcolorboxenvironment.
% Equations and theorems style