The oxidation state of P in HPO32- is-

1. +3 2. +4
3. +2 4. +5
Subtopic:  Introduction to Redox and Oxidation Number |
 85%
Level 1: 80%+
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The oxidation state of two S-atoms in Na2S2O3 is:

1. +2 and +4

2. +3 and -2

3. +4 and -2

4. +6 and -2

Subtopic:  Introduction to Redox and Oxidation Number |
Level 3: 35%-60%
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Consider the standard electrode potentials given below:
(a) \(E_{k^+/K}^o = - 2.93\ V\); \(E_{Ag^+/Ag}^o = 0.80\ V\)
(b) \(E_{Hg^{2+}/Hg}^o = 0.79\ V\); \(E_{Mg^{2+}/Mg}^o = - 2.37\ V\)  
(c) \(E_{Cr^{3+}/Cr}^o = -0.74\ V\)


The correct arrangement of increasing order for reducing power of elements is:

1. \(\mathrm{Ag}<\mathrm{Hg}<\mathrm{Cr}<\mathrm{Mg}<\mathrm{K} \)
2. \(\mathrm{Ag}>\mathrm{Cr}>\mathrm{Mg}>\mathrm{Hg}>\mathrm{K}\)
3. \(\mathrm{K}>\mathrm{Mg}<\mathrm{Cr}<\mathrm{Hg}>\mathrm{Ag} \)
4. \(\mathrm{K}<\mathrm{Mg}<\mathrm{Cr}<\mathrm{Hg}<\mathrm{Ag}\)
Subtopic:  Emf & Electrode Potential |
 76%
Level 2: 60%+
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Why does the MnO₄²⁻ ion undergo disproportionation in an acidic medium, whereas the MnO₄⁻ ion does not?
1.  Due to manganese being in its highest oxidation state in MnO₄²⁻.
2.  Due to manganese being in its highest oxidation state in MnO₄⁻
3.  Because the disproportionation reaction of MnO₄²⁻ is endothermic.
4.  Because the disproportionation reaction of MnO₄²⁻ is exothermic.
Subtopic:  Introduction to Redox and Oxidation Number |
 81%
Level 1: 80%+
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In the given reaction, what is the name of the species that bleaches the substances due to its oxidising action?
Cl2(g) + 2OH-(aq) → ClO-(aq) + Cl-(aq) + H2O(l)

1. ClO- 

2. Cl2

3. Cl-

4. Both ClO- and Cl-

Subtopic:  Oxidizing & Reducing Agents |
 51%
Level 3: 35%-60%
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The oxidation number of the atom (in bold) in the following species is given. Identify, which one is incorrectly related?

1. \(\mathbf{Cu}_{2} O\) is \(- 1\)

2. \(\mathbf{Cl} O_{3}^{-}\) is \(+ 5\)

3. \(K_{2} \mathbf{Cr}_{2} O_{7}\) is \(+ 6\)

4. \(H \mathbf{Au} Cl_{4}\) is \(+ 3\)

Subtopic:  Oxidizing & Reducing Agents |
 85%
Level 1: 80%+
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The element that does not show a disproportionation tendency is/are:

1. Cl 2. Br
3. F 4. I
Subtopic:  Oxidizing & Reducing Agents |
 86%
Level 1: 80%+
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Given below are two statements:
Assertion (A): In the representation
Fe³⁺/Fe²⁺, Ce⁴⁺/Ce³⁺ , and Cu²⁺/Cu, each pair represents a redox couple.
Reason (R): A redox couple is the combination of the oxidised and reduced forms of a substance involved in an oxidation or reduction half-cell.
 
1. Both (A) and (R) are True and (R) is the correct explanation of (A).
2. Both (A) and (R) are True, but (R) is not the correct explanation of (A).
3. (A) is True but (R) is False.
4. (A) is False but (R) is True.
Subtopic:  Introduction to Redox and Oxidation Number |
 74%
Level 2: 60%+
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Given below are two statements: 
Assertion (A): The decomposition of hydrogen peroxide to form water and oxygen is an example of a disproportionation reaction.
Reason (R): The oxygen of peroxide is in –1 oxidation state and it is converted to zero oxidation state in O2
and –2 oxidation state in H2O.

 

1. Both (A) and (R) are True and (R) is the correct explanation of (A).
2. Both (A) and (R) are True but (R) is not the correct explanation of (A).
3. (A) is True but (R) is False.
4. (A) is False but (R) is True.
Subtopic:  Redox Titration & Type of Redox |
 90%
Level 1: 80%+
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Which species is the strongest oxidizing agent based on the given standard electrode potentials?

\(E^{\ominus} values : \) \(\left(Fe\right)^{3 +} / \left(Fe\right)^{2 +} = + 0 . 77 V\)
\(I_{2} (s)/ I^{-} = + 0 . 54 V\)
\(\left(Cu\right)^{2 +} / Cu = + 0 . 34 V\)
\(\left(Ag\right)^{+} / Ag = +0 . 80 V\)


1. Fe3+
2. I2(s)
3. Cu2+
4. Ag+

Subtopic:  Application of Electrode Potential |
 83%
Level 1: 80%+
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