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

`150~ppm`

Step-by-step 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=(mg)/(L)`

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

`ppm=(150~mg)/(1~L)=~150ppm`