A non-feasible reaction among the following is:

1. 2 KI+Br22KBr+I2

2. 2 KBr+I22KI+Br2

3. 2 KBr+Cl22KCl+Br2

4. 2H2O+2F24HF+O2

Subtopic:  Introduction to Redox and Oxidation Number |
 61%
Level 2: 60%+
AIPMT - 2002
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Standard electrode potentials are:

\(F e^{+ 2} / F e\)\(E^\circ\) \(=\) \(- 0 .44\)

\(F e^{+ 3} / F e^{+ 2}\)\(E ^\circ\) \(= 0 . 77\)

Choose the correct observation when \(𝐹𝑒^{+2}\) , \(𝐹𝑒^{+3}\) and \(Fe_{(solid)}\) are kept together:

1. Fe+3 increases

2. Fe+3 decreases

3. Fe+2Fe+3 remains unchanged

4. Fe+2 decreases

Subtopic:  Application of Electrode Potential | Emf & Electrode Potential |
 68%
Level 2: 60%+
AIPMT - 2001
Hints

The oxidation states(O.S.) of sulphur in the anions SO32-, S2O42- and S2O62- follow the order:

1. S2O42-<SO32-<S2O62-

2. SO32-<S2O42-<S2O62-

3. S2O42-<S2O62-<SO32-

4. S2O62-<S2O42-<SO32-

Subtopic:  Oxidizing & Reducing Agents |
 76%
Level 2: 60%+
AIPMT - 2003
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Fluorine reacts with ice as per the following reaction

H2O(s) + F2(g) → HF(g) + HOF(g)

This reaction is a redox reaction because:

1. F2 is getting oxidized. 2. F2 is getting reduced.
3. Both (1) and (2) 

4. None of the above.
Subtopic:  Introduction to Redox and Oxidation Number |
Level 4: Below 35%
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The oxidation number of sulphur and nitrogen in H2SO5 and NO3- are respectively-

1. +6, +5 2. -6, -6
3. +8, +6 4. -8, -6
Subtopic:  Introduction to Redox and Oxidation Number |
 76%
Level 2: 60%+
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Which of the following correctly represents the formulas of (a) mercury(II) chloride and (b) thallium(I) sulphate?

1. HgCl2,  Tl2SO4

2. Hg2Cl2, Tl2SO4

3. HgCl2,  TlSO4

4. HgCl2,  Tl3SO4

Subtopic:  Introduction to Redox and Oxidation Number |
 68%
Level 2: 60%+
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Consider the following reactions:

(a) 6 CO2(g) + 6H2O(l) C6H12O6(aq) + 6O2(g)

(b) O3(g) + H2O2(l) H2O(l) + 2O2(g)

These reactions are more appropriately written in the expanded form as:

(a) 6CO2(g) + 12H2O(l) C6H12O6(aq) + 6H2O(l) + 6O2(g)

(b) O3(g) + H2O2(l) H2O(l) + O2(g) + O2(g) 

Which of the following is the most appropriate reason for writing them in expanded form?

1. Water molecules are also formed as a product in photosynthesis.

2. Water molecules are not formed as a product in photosynthesis.

3. Oxygen molecules are also formed as a product in photosynthesis.

4. Oxygen molecules are not formed as a product in photosynthesis.

Subtopic:  Balancing of Equations |
 67%
Level 2: 60%+
Hints

In the manufacture of benzoic acid from toluene, we use alcoholic potassium permanganate as an oxidant because -

1. The cost of adding an acid or a base can be reduced.

2. The reactions can proceed at a faster rate.

3. Both '1' and '2'

4. Neither '1' nor '2'

Subtopic:  Oxidizing & Reducing Agents |
 74%
Level 2: 60%+
Hints

Consider the following reactions :

2 S2O32–(aq) + I2(s)  S4O62–(aq) + 2I(aq)

S2O32–(aq) + 2Br2(l) + 5H2O(l)  2SO42–(aq) + 4Br(aq) + 10H+(aq)

The same reductant, thiosulphate reacts differently with iodine and bromine because:

1. Br2 is a stronger oxidizing agent than I2

2. I2 is a stronger oxidizing agent than Br2

3. Both '1' and '2'

4. Neither '1' nor '2'

Subtopic:  Oxidizing & Reducing Agents |
 72%
Level 2: 60%+
Hints

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The correct statement(s) about the given reaction is -

\(\small\mathrm{{X} eO_{6 (aq)}^{4 -} + 2 F^{- 1}_{(aq)} + 6 H^{+}_{(aq )} \rightarrow}~\mathrm{{X} eO_{3 (g)} + {F}_{2 (g)} + 3 H_{2} O_{(l)}}\)

1. XeO64- oxidises F-

2. The oxidation number of F increases from -1  to  zero

3. XeO64- is a stronger oxidizing agent that F-

4. All of the above

Subtopic:  Introduction to Redox and Oxidation Number | Oxidizing & Reducing Agents |
 87%
Level 1: 80%+
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