Answer:
Because it has a quickly sedative effect and it has antimicrobial effect.
Explanation:
This gas is useful because is used to trait pain, reduce anxiety and promote relaxation, slow down the body reaction, so the dentist can use it to calm down the patients.
If the patient present some injuries, this gas can help in wound healing.
A simple way to go about this is that we look at the solubility curve, on the x axis we first look at the temperature and then the corresponding value of solute/100g H2O on the y axis, from the 4 curves above only NaNO3 has a curve that can accommodate 80g of salt at 40 without being Saturated since at 40 degrees it can accommodate 105g of salt to become completely Saturated.