Question

The final compound which is responsible for Prussian blue colour in Lassaigne’s test for nitrogen​

Answer 1

Answer:

So, $$Fe_4(Fe(CN)_6]_3$$ is responsible for prussian blue colour obtained during the test of Nitrogen and Lassaigne test.

Answer 2

The final compound which is responsible for Prussian blue colour in Lassaigne’s test for nitrogen​ is Iron (III) hexacyanoferrate (II).

- In Lassagne's test, sodium cyanide first reacts with iron sulphate and forms sodium hexacyanoferrate (II).

6 CN⁻ + Fe²⁺ → [Fe(CN)₆]⁴⁻

- On heating with conc. H2SO4, some Fe²⁺ ions are converted into Fe³⁺ ions.

- These Fe³⁺ ions react with sodium hexacyanoferrate (II) to produce Iron (III) hexacyanoferrate (II) which is also known as ferriferrocyanide.

3 [Fe(CN)₆]⁴⁻ + 4 Fe³⁺ → Fe₄[Fe(CN)₆]₃

- This end product is Prussian blue in colour.