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Redox Reactions

Question
CBSEENCH11006737
Wired Faculty App

Determine the oxidation number of:
(i) Mn in KMnO4  (ii)Cr in K2Cr2O7    (iii) Cl in KClO4 ?

Solution

 (i) KMnO4.
Let the oxidation number of Mn=x
Writing the oxidation number of each atom at the top of its symbol,
          +1             x           -2
          K             Mn           O4
The algebraic sum of the oxidation number of various atoms = 0
therefore space space space space space space plus 1 space plus space straight x space plus space 4 left parenthesis negative 2 right parenthesis space equals space 0 or space space space space space space space space space space space space space space space space space straight x minus 7 space equals space 0 or space space space space space space space space space space space space space space space space space space space space space space space space space straight x space equals space plus 7

(ii) straight K subscript 2 Cr subscript 2 straight O subscript 7
Let the oxidation number of Cr = x
Writing the oxidation number of each atom at the top of tis symbol,
                         +1             x            -2
                         K2             Cr2           O7
The algebraic sum of the oxidation number of various atoms = 0
therefore space space 2 left parenthesis plus 1 right parenthesis space plus 2 left parenthesis straight x right parenthesis space plus space 7 left parenthesis negative 2 right parenthesis space equals space 0 or space space space space space space space space space space space space space space space space space space space space space 2 straight x minus 12 space equals space 0 or space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space straight x space equals space plus 6
left parenthesis iii right parenthesis space KClO subscript 4 colon
Let the oxidation number of Cl = x
Writing the oxidation number of each atom at the top of its symbol,
                     +1         x            -2
                      K          Cl            O4
The algebraic sum of the oxidation number ofvarious atoms = 0
therefore space space space plus 1 plus straight x plus 4 left parenthesis negative 2 right parenthesis space equals space 0 or space space space space space space space space space space space space space straight x space minus 7 space equals space 0 or space space space space space space space space space space space space space space space space straight x space equals space plus 7
 

Some More Questions From Redox Reactions Chapter

What are redox reactions?

What are direct redox reactions? Give one example.

What are indirect redox reactions?

Write formulas for the following compounds:
(a) Mercury (II) chloride
(b) Nickel (II) sulphate
(c) Tin (IV) oxide
(d) Thallium (I) sulphate
(e) Iron (III) sulphate
(f) Chromium (III) oxide

What are electrolytes?

What are cations and anions?

What is electrolysis?

Mention two uses of electrolysis.

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