How to Measure the Level of Sodium Nitrite Dissolved in Water

Spinach has a naturally high sodium nitrite content.

Sodium nitrite is a commonly used chemical that preserves the color of foods and prevents them from rotting. It is also naturally found in some foods, such as spinach, green cauliflower and asparagus. Although sodium nitrite is helpful in preventing food-borne diseases such as botulism, it also reacts chemically inside the human body to form carcinogens. It has also been thought to cause lung disease and provoke migraines. The content of sodium nitrite is monitored by the U.S. Government, with an acceptable level being 200 parts per million or less.

Things You'll Need

• pH paper
• Water
• Calculator

Instructions

1. Dip the pH paper inside a sample of water and hold it under for 5 seconds.

2. Compare the color of the pH paper to the color chart that should come with it. The chart assigns each color to a specific number. If your pH paper does not come with a chart, estimate the pH. Very red is a pH of 0 and very blue is a pH of 14. Green indicates a pH of 7.

3. Take 10 to the power of your pH multiplied by negative 1 (10^(-1*pH)). Subtract this number from 14. This number is the concentration of hydroxide ions (residue from chemical reactions involving hydrogen nitrite) in your water.

4. Square the number of hydroxide ions and multiply by 10 to the power of (-6.61) (the Kb of nitrite). This number is equal to the concentration of sodium nitrite in your water in moles (6.02 times 10 to the 23rd atoms) per liter.

References

• Chemical Reactions: Acid/Base
• Hydrogen Nitrite Formula