Chem redox question
2012-01-05 10:15 pm
圖片參考：http://imgcld.yimg.com/8/n/HA07275166/o/701201050036913873419130.jpg
For the above set-up,
In test tube A, Nickel is heated together with conccentrated sulphuric acid.
The gas produced is directed to test tube B
And the excess gas is directed to test tube C
1) What is the observation in test tube A, B and C, respectively
2) Write the chemical equations for the reaction in test tube A, B and C, respectively.
THX!~
回答 (3)
2012-01-06 9:35 am
✔ 最佳答案
1)Test tube A :
The nickel dissolves. The solution changes from colourless to green. Acolourless gas is evolved.
Test tube B :
No observation change
Test tube C :
The solution changes from deep purple to colourless.
=====
2)
Test tube A :
Ni + 2H2SO4 → NiSO4 + 2H2O+ SO2
Test tube B :
No reaction
Test tube C:
2MnO4^- + 5SO2 + 2H2O → 2Mn^2+ + 5SO4^2-+ 4H^+
or: 2KMnO4 + 5SO2 + 2H2O → K2SO4+ 2MnSO4 + 2H2SO4
2012-01-07 01:10:46 補充：
看錯了，答案更正如下：
1)
Test tube C :
The solution changes from orange to green.
2)
Test tube C:
Cr2O7^2- + 2H^+ 3SO2 → 2Cr^3+ + H2O + 3SO4^2-
or: K2Cr2O7 + H2SO4 + 3SO2 → K2SO4 + Cr2(SO4)3 + H2O
參考: andrew, andrew
2012-01-06 1:56 pm
就算題目問到都不一定有reaction, 別被題目唬窒, 或者夾硬寫/作一條"新" equation (會有人寫Fe(II) 變Fe(III)), 咁就中招.
2012-01-06 6:45 am
Test tube B 是否有誤?
收錄日期: 2021-04-13 18:27:38
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