6 votes
Accepted

Oxidation states of Thiosulphate

If the last paragraph in your quotation is meant to be the book's answer, I would stain that text with my intensely colored, anthocyanin-rich cranberry jam*. I would find either $-1$ and $+5$ or $0$ ...
Oscar Lanzi's user avatar
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4 votes
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When HI reacts with H2SO4, why is the sulphate ion reduced to hydrogen sulphide instead of sulfur dioxide?

The book intitled Qualitative Analysis emitted by F. P. Treadwell in $1924$ mentions in the chapter Iodine (p. 323) that the reaction depends on the relative amount of $\ce{H2SO4}$. In the presence of ...
Maurice's user avatar
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4 votes

Why does Ascorbic Acid on paper turn brown when heated?

While I did not find sources that directly address your question, what I read about durability of paper seems to say that the acidity of the ascorbic acid would weaken the paper, accelerating the ...
Karsten's user avatar
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4 votes
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Oxidation Number of the middle carbon in $\ce{C3O2}$ (Carbon Suboxide)

First off, carbon suboxide is much closer to being linear than formally isoelectronic species such as $\ce{N5^+}$. The energy difference between linear and bent conformations is so small it gets ...
Oscar Lanzi's user avatar
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3 votes
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Stability of H3MnO4, H2MnO4, HMnO4

One difference between manganese(V) and phosphorus(V) is the former can undergo disproportionation with higher manganese oxidation states available. Not only $\ce{Mn^VO4^{3-}}$ but also $\ce{Mn^{VI}O4^...
Oscar Lanzi's user avatar
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3 votes

Why is the +3 oxidation state of Cerium more stable than +4?

The question is a problem, it contains a fact which can not be trusted. It has the assumption that one oxidation state is more stable than another oxidation state. The problem is that the relative ...
Nuclear Chemist's user avatar
3 votes
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Why does balancing the reduction of dichromate(VI) to chromium(III) require four water molecules among the products?

$$\ce{Cr2O7^2–(aq) + 3 HNO2(aq) + 5 H+(aq) -> 2 Cr^3+(aq) + 3 NO3–(aq) + 4 H2O} $$ The left side has $1\cdot7 + 3\cdot2 = 13$ oxygen atoms and $3\cdot1 + 5\cdot1 = 8$ hydrogen atoms. The right side ...
Karsten's user avatar
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2 votes
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Why does balancing the oxidation of dichromate(VI) to chromium(III) require six iron atoms?

I would like to go back to your original demand. On the first line, there was a title : "The problem". The second line is : "Balance the chemical equation using oxidation numbers". ...
Maurice's user avatar
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2 votes
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What is the oxidation state of atoms in interstitial transition compounds?

In the case of titanium carbide $\ce{TiC}$, there is a slight reaction with water to form methane, consistent with an oxidation state assignment $\ce{Ti^{IV}C^{-IV}}$, and even Group 5 carbides with ...
Oscar Lanzi's user avatar
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2 votes

Stability of H3MnO4, H2MnO4, HMnO4

Manganese doesn't like to be in +5 and +6 O.S. and the acid form of hypomanganate and manganate anion cannot exist due to rapid disproportionation. So, they exist as salts of alkali metals. Manganese ...
Nilay Ghosh's user avatar
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2 votes

Why is the +3 oxidation state of Cerium more stable than +4?

Ce has electronic configuration [Xe]$\ce {4f^1}\ce{5d^1}\ce{6s^2}$. Electronic configuration of the Ce$^{3+}$ is [Xe]$\ce{4f^1}$ while that of Ce$^{4+}$ is [Xe]$\ce{4f^0}\ce{5d^0}\ce{6s^0}$ or simply [...
Proscionexium's user avatar
1 vote

Find cell configuration notation for permanganate in acidic medium

Because I heard people saying that since the anode already has a solid substance (solid iodine) it's not necessary to add platinum to the anode. I digress because I think platinum is necessary for the ...
Metal Storm's user avatar
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1 vote
Accepted

Oxidizing property of permanganate

The iodate ion needs $\ce{H+}$ to give a reducing half-equation with electrons, in an equation like : $$\ce{6 e- + IO3^- + 6 H+ -> I^- + 3 H2O}$$ If no $\ce{H+}$ are available, the iodate ion may ...
Maurice's user avatar
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1 vote

When HI reacts with H2SO4, why is the sulphate ion reduced to hydrogen sulphide instead of sulfur dioxide?

As @Oscar said, hydrogen iodide (or iodide ion) is much stronger reducing agent than hydrogen bromide (or bromide ion). So the sulfuric acid reduce through a rather complicated pathway than just ...
Nilay Ghosh's user avatar
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1 vote
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Specifying which compound is oxidized/reduced in a redox reaction

Both concepts can be accepted. Some chemists state that Sulfur atom is oxidized and the Manganese atom is reduced. Some other chemists may state that $\ce{SO2}$ is oxidized, and permanganate ion is ...
Maurice's user avatar
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1 vote

Specifying which compound is oxidized/reduced in a redox reaction

If you can separate the redox reaction into a reduction and an oxidation half reaction, you can say that the entire molecular entity undergoes reduction or oxidation. $\rm{2 \overset{+7}{Mn} \overset{...
Karsten's user avatar
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1 vote

Are there known compounds of caesium with oxidation number >1?

Not known compounds, but Moock and Seppelt[1] have some evidence that at least some short-lived caesium(>I) species exists. In both Ref. [1] and an earlier work cited by the authors, ...
Oscar Lanzi's user avatar
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