Fluoridation is the process of adding fluorine compounds to drinking water to fight tooth decay. a concentration of 1 ppm of fluorine is sufficient for the purpose (1 ppm means one part per million, or 1 g of fluorine per 1 million g of water). the compound normally chosen for fluoridation is sodium fluoride, which is also added to some toothpastes. calculate the quantity of sodium fluoride in kilograms needed per year for a city of 50,000 people if the daily consumption of water per person is 150 gal. what percent of the sodium fluoride is "wasted" if each person uses only 6.0 l of water a day for drinking and cooking (sodium fluoride is 45.0 percent fluorine by mass; 1 gal= 3.79 l; 1 year =365 days; 1 ton =2000 lb; 1 lb =453.6g; density of water =1.0 g/ml)?