CBSE Class 12 Chemistry 2020 Outside Delhi Set 1 Solved Paper

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Question : 23
Total: 37
Write the balanced chemical equations involved in the preparation of KMnO4 from pyrolusite ore (MnO2).
OR
Write the balanced ionic equations showing the oxidising action of acidified dichromate (Cr2O72) solution with
(i) Iron (II) ion and (ii) Tin (II) ion.
Solution:  
2MnO2+4KOH+O22K2MnO4 +2H2O
3K2MnO4+2CO22KMnO4+
MnO2
(ppt)
+2K2CO3
OR

(i) Cr2O72+14H++6Fe2+2Cr3+ +6Fe3++7H2O
(ii) Cr2O72+3Sn2++14H+2Cr3++3Sn4+ +7H2O
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