Among the following, In which iron has the lowest oxidation state?

1. Fe(CO)₅

2. Fe₂O

3. K₄Fe(CN)₆

4. FeSO₄.(NH₄)₂SO₄.6H₂O

Reducing agent among the following is -

The equivalent mass of a reductant or an oxidant is given by:

1. Eq. mass = $\frac{molar mass of reduc\tan t or oxidant}{no. of electrons lost or gained by 1 molecule of reduc\tan t or oxidant}$

2. Eq. mass = $\frac{molar mass}{valence}$

3. Eq. mass = $\frac{molar mass}{total charge on cation or anion}$$$

4. All of the above

NaH+ H₂O $\to$NaOH + H₂:

The correct statement for above mentioned reaction among the following is-

1. H^- is oxidised

2. Na⁺ is reduced

3. Both NaH and H₂O are reduced 

4. None of the above

When an acidified solution of ferrous ammonium sulphate is treated with KMnO₄ solution, the ion that gets oxidised is:

1. Fe²⁺

2. S${\mathrm{O}}_4^{2-}$

3. N${\mathrm{H}}_4^{+}$

4. Mn${\mathrm{O}}_4^{-}$

In the reaction, 

Cr₂${\mathrm{O}}_7^{2-}$ +14H⁺ + 6I^- $\to$2Cr³⁺ + 7H₂O + 3I₂,

Which element is reduced?

1. I

2. O

3. H

4. Cr

2Na₂S₂O₃ + I₂ $\to$ Na₂S₄O₆ + 2NaI,

the oxidation state of sulphur in tha above reaction:

1. Decreases

2. Increases

3. Remain unchanged

4. None of the above

In the aluminothermic process, aluminium acts as:

1. an oxidising agent

2. a flux

3. a reducing agent

4. a solder

Disproportionation reaction(s) among the following is/are represented by -

1. Cl₂ + 2OH^- $\to$ClO^- + Cl^- + H₂O

2. Cu₂O(s) + 2H⁺ $\to$Cu²⁺ + Cu(s) + H₂O

3. 2HCuCl₂ $\underset{\mathrm{water}}{\overset{\mathrm{Dilution} \mathrm{with}}{\to }}$ Cu + Cu²⁺ + 4 Cl^- +  2H⁺

4. All of the above

In a redox change, the oxidant K₂Cr₂O₇ is always reduced to:

1. Cr⁵⁺

2. Cr⁴⁺

3. Cr³⁺

4. Cr²⁺