In what scenario would you be adding a large volume of water to a small volume of acid.
If say, you were using sulfuric acid to acidify alkaline water, and you put the acid into a water tank first, and then added water. Or if you were to fill a lead-acid battery and pour in the higher concentrated sulfuric acid first, and then add water. Acids come in variable strengths. Vinegar and lemon juice being mild, some hot tub and pool chemicals being stronger and typically in dry acid form, and then the likes of common battery acid, which is typically strong sulfuric acid (it will burn you if you get it on your skin). Some industrial drain cleaners that I have used also have a high concentration of sulfuric acid in them. I used to dissolve sponges and mop heads with that stuff when I was a dishwasher for fun.