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Tardigrade
Question
Chemistry
Which of the following statement(s) is (are) correct with reference to the ferrous and ferric ions
Q. Which of the following statement(s) is (are) correct with reference to the ferrous and ferric ions
2102
239
The d-and f-Block Elements
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A
F
e
3
+
gives brown colour with potassium ferricyanide
45%
B
F
e
2
+
gives blue precipitate with potassium ferricyanide
49%
C
F
e
3
+
gives red colour with potassium thiocyanate
45%
D
F
e
2
+
gives brown colour with ammonium thiocyanate
12%
Solution:
Ferrous salts react with potassium ferricyanide to give blue colouration due to the formation of Turnbull’s blue in this reaction, first ferrous salt is oxidised to ferric salt by the ferricyanide ion which itself is reduced to ferrocyanide.
F
e
+
2
+
Ferricyanide
[
F
e
(
CN
)
6
]
3
−
→
F
e
+
3
+
Fenocyanide
[
F
e
(
CN
)
6
]
4
−
F
e
+
3
+
[
F
e
(
CN
)
6
]
4
−
→
{
F
e
[
F
e
(
CN
)
6
]
}
−
F
e
+
3
+
[
F
e
(
CN
)
6
]
4
−
+
K
+
→
Pot. ferric feno cyanide or Turnbull’s blue
K
{
F
e
[
F
e
(
CN
)
6
]
}
Ferric ions react with potassium thiocyanate to give blood red colouration due to the formation of ferric thiocyanate
F
e
C
l
3
+
3
K
CNS
→
Ferric thiocyanate (Blood red)
F
e
(
CNS
)
3
+
3
K
Cl