Notebook Theme

Experiment No. N

Analysis of Manganese(II) Nitrate (Mn(NO₃)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
Add conc. H₂SO₄ to the solution and boil with a few copper turnings/chipsOn heating, brown fumes (NO₂) are evolved in excess and the solution becomes blueNO₃⁻ may be present
Confirmatory Test
Brown Ring Test
Take 1 mL of salt solution, add 2 mL conc. H₂SO₄, cool, then add freshly prepared ferrous sulphate solution along the sides
Brown ring is formed at the junction of the two solutionsNO₃⁻ is confirmed

Test of Cation

ExperimentObservationInference
Original solution + H₂S gas in presence of NH₄OHBlack or flesh-coloured precipitate is formedGroup IV cation may be present
Confirmatory Test
Sodium Hydroxide Test
Dissolve the precipitate in dilute HCl by boiling and add NaOH in excess
White precipitate forms first, then turns brown on standingPresence of Mn²⁺ is confirmed

Result

The given salt contains Mn²⁺ ions as cation and NO₃⁻ ions as anion. The salt is Mn(NO₃)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.