Analytical Chemistry Question 165
Question: An aqueous solution of a salt X turns blood red on treatment with $ CN{S^{-}} $ and blue on treatment with $ K_4[Fe{{( CN )}_6}] $ . X also gives a positive chromyl chloride test. The salt X is:
Options:
A) $ CuCl_2 $
B) $ FeCl_3 $
C) $ Cu{{(NO_3)}_2} $
D) $ Fe{{(NO_3)}_3} $
Show Answer
Answer:
Correct Answer: B
Solution:
[b] $ F{e^{3+}} $ , radical gives blood red with $ CN{S^{-}} $
$ F{e^{3+}}+3CN{S^{-}}\xrightarrow{{}}\underset{\begin{smallmatrix} Ferricsulphocyamde \\ ( Bloodredcolouration ) \end{smallmatrix}}{\mathop{Fe{{(CNS)}_3}}} $
$ F{e^{3+}} $ gives blue colour on treatment with $ K_4[Fe{{(CN)}_6}] $
$ 4F{e^{3+}}+3K_4[ Fe{{( CN )}_6} ]\xrightarrow{{}} $
$ \underset{\begin{smallmatrix} Ferricferrocyanide \\ ( Prussianblue ) \end{smallmatrix}}{\mathop{12{K^{+}}+Fe_4{{[ Fe{{( CN )}_6} ]}_3}}} $
$ C{l^{-}} $ radical gives chromyl chloride test.
BETA
