Sodium nitroprusside when added to an alkaline solution of sulphide ion gives red coloured solution. The red colouration is due to the formation of:

Question

Vimal Swarnkar · Accepted Answer

(a) Na₄[Fe(CN)₅(NOS)]. Sodium nitroprusside Na₂[Fe(CN)₅NO] + S²⁻ (alkaline) → Na₄[Fe(CN)₅NOS], a violet/purple-red complex. S²⁻ adds to the NO ligand → (a). Remember: same test is used for S in Lassaigne's extract.

Answer

(b) Na₂[Fe(CN)₅(NO)]

Answer

(c) Na₄[FeCl₅(NOS)]

Answer

(d) [Fe(H₂O)₅(NO)]SO₄

Geo-Scientist Prelims 2020 Chemistry Q20: Sodium nitroprusside when added to an alkaline solution of sulphide…

QuestionQualitative analysis / sulfide test