The photographs below

(a) show what occurs when a solution of iron(III) nitrate is treated with a few drops of aqueous potassium thiocyanate. The nearly colorless iron(III) ion is converted to a red [Fe(H₂O)₅SCN]²⁺ ion. (This is a classic test for the presence of iron(III) ions in solution.)

(a) As more KSCN is added to the solution, the color becomes even more red. Explain this observation.
(b) Silver ions form a white precipitate with SCN−ions. What would you observe on adding a few drops of aqueous silver nitrate to a red solution of [Fe(H₂O)₅SCN]⁺ ions? Explain your observation.

Transcribed Image Text:

[Fe(H₂O)]³+ (aq) + SCN-(aq) = [Fe(H₂O)5SCN]2+(aq) + H₂O(l)