Which of the following reactions does not represent a redox change?

1. CaCO₃ $\to$CaO + CO₂

2. 2H₂ + O₂ $\to$2H₂O

3. Na + H₂O $\to$ NaOH + \(\frac{1}{2}\)H₂

4. MnCl₃ $\to$ MnCl₂ + \(\frac{1}{2}\)Cl₂

Reducing agent among the following is -

The oxidation number of carbon in C₃O₂  and Mg₂C₃ are respectively:

1. -4/3, +4/3 

2. +4/3, -4/3

3. -2/3, +2/3

4. -2/3, +4/3

Which of the following is not an intramolecular redox reaction?

1. NH₄NO₂ $\to$N₂ + 2H₂O

2. 2Mn₂O₇ $\to$4MnO₂ + 3O₂

3. 2KClO₃ $\to$2KCl + 3O₂

4. $2{\mathrm{H}}_2{\mathrm{O}}_2$ $\to$2H₂O + O₂

 The compound having oxygen in - 1 oxidation state is:-

Which is the correct set that can only act as an oxidant? 

In the given reaction,

xBrO_3^- + yCr⁺³ + zH₂O $\to$Br₂ + CrO₄^2- + H⁺

The coefficients x, y, and z are respectively-

1. 6, 10, 11

2. 6, 10, 20

3. 6, 8, 22

4. 6, 10, 22

In the following reaction

Al + Fe₃O₄ $\to$Al₂O₃ + Fe

The total number of electrons transferred will be-

1. 6

2. 8

3. 8/3

4. 24

In the conversion, H₂SO₄ $\to$H₂S₂O₈ which process occurs?

1. Oxidation

2. Reduction

3. Oxidation as well as reduction

4. Neither oxidation nor reduction

If 10 gm of V₂O₅ is dissolved in acid and is reduced to V²⁺ by zinc metal, how many moles of I₂ could be reduced by the resulting solution if it is further oxidized to VO²⁺ ions?

[Assume no change in state of Zn²⁺ions] (V = 51, O =16, I = 127) :