Question

Which of the following statement(s) is/are correct with reference to the ferrous and ferric ions ?

• A. $F{e}^{3+}$ gives brown colour with potassium ferricyanide
• B. $F{e}^{2+}$ gives blue colour with potassium ferricyanide
• C. $F{e}^{3+}$ gives red colour with potassium thiocyanate
• D. $F{e}^{2+}$ gives brown colour with ammonium thiocyanate

Answer 1

Answer: (B), (C)

$F{e}^{3+}$ gives red colour with potassium thiocyanate

$F{e}^{2+}$ on reaction with potassium ferricyanide will give a dark blue precipitate.This precipitate is known as Turnbull's blue and it is identical to Prussian blue.
$K^{+}+F{e}^{2+}+\left[Fe\right(CN{)}_6{]}^{3-}\rightleftharpoons KFe\left[Fe\right(CN{)}_6]$
$F{e}^{3+}$ on reaction with potassium thiocyanate $\left(KSCN\right)$ gives a blood red solution
$FeC{l}_3+KSCN\to \underset{\text{Blood red color}}{Fe(SCN{)}_3}+3KCl$
Options (b) and (c) are correct.