PROTOCOL N° 8

IDENTIFICATION OF NO3- AND NO2- IN A TEST SOLUTION AND IN A WATER SAMPLE

ATTENTION: Sodium hydroxide, used in the identification of NO3- and NO2- can produce severe burning. Avoid contact with the skin.

Risk code(s): R 35
Safety code(s): S 18, 27, 28, 37

REAGENTS

  • Finely divided aluminium
  • Nitrate and nitrite test solution
  • Sodium hydroxide aqueous solution, 6 mol/dm3 NaOH
  • Universal indicator paper

PROCEDURE

  1. Identification of NO3- and NO2- in a test solution

    2. 1.1  Place 10 drops of the test solution containing nitrate and nitrite in a test tube,

    1.2  Add 20 drops of the sodium hydroxide solution,

    1.3  Add one small piece of aluminium,

    1.4  Place one wet strip of the universal indicator paper over the top of the test tube,

    1.5  Heat the test tube slightly with an alcohol lamp until the indicator paper changes colour,

    1.6  Record the observations.

  2. Verification of the presence of NO3- and NO2- in a water sample

    3. 2.1  Place the 10 drops of the water sample in a test tube,

    2.2  Repeat procedures 1.2. to 1.6.

CONCLUSIONS

Does the analyzed water contain NO3- and NO2- , Yes or No ?