When reducing V(V) to V(II) ions, Zinc was used. Why do we have to filter out the Zinc before adding the KMno4? And what's the purpose of adding KMno4?
This question came up in an end of chapter test and I can't seem to find an answer for it
Reaction between Potassium Permanganate and Vanadium (II)?
2016-05-06 3:40 pm
回答 (1)
2016-05-06 4:14 pm
When reducing V(V) to V(II) ions, Zinc was used. Why do we have to filter out the Zinc before adding the KMnO₄?
This is to prevent the redox reaction between excess zinc and acidified KMnO₄.
5Zn(s) + 2MnO₄⁻(aq) + 16H⁺(aq) → 5Zn²⁺(aq) + 2Mn²⁺(aq) + 8H₂O(l)
====
And what's the purpose of adding KMnO₄?
The acidified KMnO₄ solution would oxidize the vanadium(II) ions to dioxovanadium(V) ions.
5V²⁺(aq) + 3MnO₄⁻(aq) + 4H⁺(aq) → 5VO₂⁺(aq) + 3Mn²⁺(aq) + 2H₂O(l)
This is to prevent the redox reaction between excess zinc and acidified KMnO₄.
5Zn(s) + 2MnO₄⁻(aq) + 16H⁺(aq) → 5Zn²⁺(aq) + 2Mn²⁺(aq) + 8H₂O(l)
====
And what's the purpose of adding KMnO₄?
The acidified KMnO₄ solution would oxidize the vanadium(II) ions to dioxovanadium(V) ions.
5V²⁺(aq) + 3MnO₄⁻(aq) + 4H⁺(aq) → 5VO₂⁺(aq) + 3Mn²⁺(aq) + 2H₂O(l)
收錄日期: 2021-04-18 14:48:33
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20160506074015AArSawO