Calculate the percentage purity of the sodium nitrite used

To calculate the percentage purity of the sodium nitrite, we need the initial mass of the impure sodium nitrite that was used to prepare solution H. This value was not provided in the original problem statement or the image.

In the previous answer, I demonstrated how to calculate the mass of pure sodium nitrite present in 1 dm³ of solution H, which was 2.895 g.

To find the percentage purity, you would use the formula:

$$\text{Percentage purity} = \frac{\text{Mass of pure NaNO}_2 \text{ in 1 dm}^3}{\text{Mass of impure NaNO}_2 \text{ used to make 1 dm}^3} \times 100\%$$

Since the "Mass of impure $\text{NaNO}_2$ used to make 1 dm³" is missing, the percentage purity cannot be calculated.