...allow me to take a whack at this (bearing in mind that I've been
conscious now for a mere 17 minutes and may not be up to full form)
...the truth of the statement
depends on how equivalence is defined. Within a particular context
(in this case symbolic logic) the equivalence is manifest through the
extreme abstraction of the properties of entity [A]. In the example
you used in your original proposal you offered a polar bond in atomic
structure as a possible substitute context, but even in that
minimalist context the ground for equivalence needs to be defined.
...f'rinstance, in an atomic pair-bond the entities might be
equivalent in charge and strength of bonding but are not necessarily equal in properties that have no bearing on that particular context.
...unless you are supposing that it is possible for two seperate
entities to be identical, a concession which I'm unwilling to make.
...it's not enough to say 2 things ARE equivalent and offer that as
an example of a truth, HOW those things are equivalent is a necessary piece of information.(and one relative to context)