I notice an article on the Globe and Mail's website, there is not enough acid in a can of Mountain Dew to dissolve a mouse.
However, if you read the article, that isn't actually what they claimed:
"As Dr. McGill explains, if a mouse is submerged in a fluid with the acidity of Mountain Dew, after 4 to 7 days in the fluid the mouse will have no calcium in its bones and bony structures, the mouse's abdominal structure will rupture, and its cranial cavity (head) is also likely to rupture... By 30 days of exposure to the fluid, all of the mouse's structures will disintegrate to the point where the structures (excepting possibly a portion of the tail) will not be recognizable and, therefore, the animal itself will not be recognizable. Instead, after 30 days in the fluid, the mouse will have been transformed into a 'jelly-like' substance."
That statement refers to a 'fluid with the acidity of Mountain Dew', which doesn't even address the question of whether it is the same acid or not, simply the same pH level, and furthermore, there is no mention of how much of this 'fluid' they are talking about. It's the kind of scientific claim that would only be used in a legal trial, hoping that whoever hears it doesn't actually understand what is being said and not said.