Misc: Which opera was comissioned by the Khedive of Egypt?

Questions

carbonated water, with nothing else in it, can dissolve---------- , talc, and many other low-moh's hardness minerals?

carbonated water, with nothing else in it, can dissolve limestone, ---------- , and many other low-moh's hardness minerals?

carbonated water, with nothing else in it, can dissolve limestone, talc, and many other low-moh's hardness----------?

drinking water after eating reduces the ---------- in your mouth by 61 percent?

drinking water after eating reduces the acid in your mouth by ---------- percent?