Question

A solution is made by dissolving 2.5 mg sodium fluoride (NaF) in 5.0 L of water at 20.0°C. What is the fluoride ion concentration in ppm of the resulting solution, given that NaF is 45.0% fluoride ion by mass, and the density of water of 1.00 kg/L?

Answer 1

0.28125 ppm

Step-by-step explanation:

Answer 2

0.23 ppm

Step-by-step explanation:

2.5 mg NaF/5.0 L H₂O ×

45.0 mg F/100.0 mg NaF ×

1.00 L H2O/1.00 kg H2O

= 0.23 mg F/1.00 kg H2O

= 0.23 ppm