JEE Main & Advanced Chemistry Redox Reactions / रेडॉक्स अभिक्रियाएँ Sample Paper Topic Test - Redox Reactions

Oxidation number of Fe in \[{{[Fe{{(CN)}_{6}}]}^{-3}},\]\[{{[Fe{{(CN)}_{6}}]}^{-4}},\,{{[Fe(SCN)]}^{+2}}\] and \[{{[Fe{{({{H}_{2}}O)}_{6}}]}^{+3}}\] respectively would be-

A) +3, +2, +3 and +3

B) +3, +3, +3 and +3

C) +3, +2, +2 and +2

D) +2, +2, +2 and +2

Correct Answer: A

Solution :

[a] O.N. of Fein:

\[{{\left[ Fe{{\left( CN \right)}_{6}} \right]}^{3-}}\Rightarrow x-6=-3\Rightarrow x=+3\]

\[{{\left[ Fe\left( SCN \right) \right]}^{2+}}\Rightarrow x-1=+2\Rightarrow x=+3\]

\[{{\left[ Fe{{\left( {{H}_{2}}O \right)}_{6}} \right]}^{3+}}\Rightarrow x+0=+3\Rightarrow x=+3\]

Thus, option [a] is correct.