You can boil the salt water. The water will evaporate while the salt will be left behind because it's a solid. Salt has a much higher boiling point than water (2,575° F), so that's why it won't evaporate with the water.
I pick but I'm not sure about it though 1and3
Answer: P2O5
Explanation: You divide both subscripts by 2 to get the empirical formula.
