Question

A stock solution contains a mixture of ~100 ppm chloride, fluoride, nitrite, bromide, nitrate and phosphate anions. In order to prepare 1 L of 100 ppm nitrite stock solution, you weigh out 150.0 mg of NaNO2. The actual concentration of nitrite would be:______.

Answer 1

Answer:

$150~ppm$

Explanation:

The first step is to draw the ionization reaction of $NaNO_2$, so:

$NaNO_2~->~Na^+~+~NO_2^-$

The molar ratio between $NaNO_2$ and $NO_2^-$ is 1:1

The next step is the calculation of the concentration. We have to remember that the formula of ppm is:

$ppm=\frac{mg}{L}$

In this case we will have a mass of 150 mg and a volume of 1 L so:

$ppm=\frac{150~mg}{1~L}=~150ppm$