The oxidation states of the central atom in the given species are, respectively:

${\mathrm{H}}_4{\mathrm{P}}_2{\mathrm{O}}_7$  $\mathrm{and}$ ${\mathrm{H}}_2{\mathrm{S}}_2{\mathrm{O}}_7$

KI₃, H₂S₄O₆

The oxidation numbers of iodine and sulphur in the above compounds are, respectively:

1. $\dfrac{1}{3}$ ; 4
2. 2.5 ; $\dfrac{1}{3}$
3. $-\dfrac{1}{3}$ ; 2.5
4. 2.5 ; 3

The oxidation state of P in ${\mathrm{HPO}}_3^{2-}$ is-

Which of the following reactions does not involve disproportionation process?

1. ${\mathrm{Cl}}_2+{\mathrm{OH}}^{-}\to {\mathrm{Cl}}^{-}+{\mathrm{ClO}}_3^{-}+{\mathrm{H}}_2\mathrm{O}$

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

3. $2{\mathrm{Cu}}^{+}\to {\mathrm{Cu}}^{2+}+\mathrm{Cu}$

4. ${\left({\mathrm{NH}}_4\right)}_{2}C{r}_2{O}_7\to {\mathrm{N}}_2+{\mathrm{Cr}}_2{\mathrm{O}}_3+4{\mathrm{H}}_2\mathrm{O}$

The oxidation number of sulphur and nitrogen in H₂SO₅ and NO₃^- are respectively-

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

Fluorine reacts with ice as per the following reaction

H₂O(s) + F₂(g) → HF(g) + HOF(g)

This reaction is a redox reaction because-

Which element exhibits both positive and negative oxidation states?
1. Cs
2. Ne
3. I
4. F