[Timangi99]

So recently we mixed Novalucol (an antacid) with HCL, and we measured the pH as we did it.

Funny though, that a form of film formed on top of the solution, anyone have any ideas what
that might have been about?

I provide a list (not complete) of Novalucols chemical composition:
Magnesium hydroxide
Calcium carbonate
Xylitol
Mannitol
Sorbitol
Magnesiumtearate

[Arkcon]

What do you know, about the physical and chemical properties, of each of those components, that can give you a hint about the film you saw on the surface?  Were you taught about any of them?  Can you infer some properties from their names?

I can see you're new to this forum, so I'd like to let you know -- we don't just give answers on this board, we try to give hints, so that you learn more, and end up better off.  A little googling, for each chemical listed above, will lead you to the answer to your question, and more answers, which you'll need sooner or later.

Since I've worked in the analysis of compounded pharmaceuticals myself in an industrial setting, I can tell you that the answer is there, if you look for it.