Question

A 500 g solution has 0.1 g fluoride concentration. Then fluoride concentration in term of ppm will be:

• A. $200\text{ppm}$
• B. $100\text{ppm}$
• C. $400\text{ppm}$
• D. $50\text{ppm}$

Answer 1

The correct option is A $200\text{ppm}$

Parts per million $=\frac{\text{mass of the solute}}{\text{mass of the solution}}\times {10}^6$

Mass of the solute $=0.1\text{g}$
Mass of the solution $=500\text{g}$

$F^{-}$ concentration $=\frac{0.1}{500}\times {10}^6\text{ppm}=200\text{ppm}$