Built by Aabis
Notebook Theme

Experiment No. N

Analysis of Copper(II) Nitrite (Cu(NO₂)₂)

Aim

To determine the presence of anion and cation in the given salt

Preliminary Test

  • Odor: Odorless
  • Texture: Crystalline
  • Color: White
  • Solubility: Soluble in water

Test of Anion

ExperimentObservationInference
Warm the solid salt with dilute H₂SO₄Brown fumes of NO₂ are evolvedNO₂⁻ may be present
Confirmatory Tests
Potassium Iodide Starch Test
Take evolved gas and add KI + starch solution acidified with acetic acid		Blue colour appearsNO₂⁻ is confirmed
Sulphanilic Acid / 1-Naphthylamine Test
Acidify 1 mL of water extract with acetic acid and add sulphanilic acid solution followed by 1-naphthylamine reagent		Red colour is formedNO₂⁻ is confirmed

Test of Cation

ExperimentObservationInference
Original solution + H₂S gas in presence of dil. HClBlack precipitate of Group-II A is formedGroup-II cation may be present
Confirmatory Test
Potassium Ferrocyanide Test
Dissolve the black precipitate in dilute nitric acid, boil the filtrate and then add potassium ferrocyanide		Chocolate brown precipitatePresence of Cu²⁺ is confirmed

Result

The given salt contains Cu²⁺ ions as cation and NO₂⁻ ions as anion. The salt is Cu(NO₂)₂.

Precautions

  1. Handle the chemicals with care.
  2. Don't use excess of chemicals.
  3. Keep the mouth of the test tube away from the face.