Match Column I with Column II for the oxidation states of the central atoms.
| Column I | Column II | ||
|---|---|---|---|
| A. | $$ \mathrm{Cr}_2 \mathrm{O}_7^{2-} $$ |
1. | +3 |
| B. | $$ \mathrm{MnO}_4^{-} $$ |
2. | +4 |
| C. | $$ \mathrm{VO}_3^{-} $$ |
3. | +5 |
| D. | $$ \mathrm{FeF}_6^{3-} $$ |
5. | +6 |
| 6 | +7 |
$$\mathrm{A.\to(4)\quad B.\to(5)\quad C.\to(3)\quad D.\to(1)}$$
Suppose that $x$ be the oxidation states of central atoms.
A. Oxidation number of Cr in $\mathrm{Cr}_2 \mathrm{O}_7^{2-}$
$$\begin{aligned} 2 x+7(-2) & =-2 \\ 2 x-14 & =-2 \\ 2 x & =+12 \\ x & =+6 \end{aligned}$$
$$\begin{aligned} &\text { B. Oxidation number of } \mathrm{Mn} \text { in } \mathrm{MnO}_4^{-}\\ &\begin{aligned} x+4(-2) & =-1 \\ x-8 & =-1 \\ x & =+7 \end{aligned} \end{aligned}$$
$$\begin{aligned} &\text { C. Oxidation number of } \mathrm{V} \text { in } \mathrm{VO}_3^{-}\\ &\begin{aligned} x+3(-2) & =-1 \\ x-6 & =-1 \\ x & =+5 \end{aligned} \end{aligned}$$
$$\begin{aligned} &\text { D. Oxidation number of } \mathrm{Fe} \text { in } \mathrm{FeF}_6^{3-}\\ &\begin{aligned} x+6(-1) & =-3 \\ x-6 & =-3 \\ \text { or }\quad x & =+3 \end{aligned}\\ \end{aligned}$$
Match the items in Column I with relevant items in Column II.
| Column I | Column II | ||
|---|---|---|---|
| A. | Ions having positive charge | 1. | +7 |
| B. | The sum of oxidation number of all atoms in a neutral molecule | 2. | $$-$$1 |
| C. | Oxidation number of hydrogen ion (H$$^+$$) | 3. | +1 |
| D. | Oxidation number of fluorine in NaF | 4. | 0 |
| E. | Ions having negative charge | 5. | Cation |
| 6. | Anion |
A. $\rightarrow$ (5)
B. $\rightarrow$ (4)
C. $\rightarrow$ (3)
D. $\rightarrow$ (2)
E. $\rightarrow(6)$
A. lons having positive charge - Cation
B. The sum of oxidation number of all atoms in a neutral molecule - Zero
C. Oxidation number of hydrogen ion $\left(\mathrm{H}^{+}\right)-+1$
D. Oxidation number of fluorine in $\mathrm{NaF}--1$
E. lons having negative charge - Anion
Assertion (A) Among halogens fluorine is the best oxidant.
Reason (R) Fluorine is the most electronegative atom.
Assertion (A) In the reaction between potassium permanganate and potassium iodide, permanganate ions act as oxidising agent.
Reason (R) Oxidation state of manganese changes from +2 to +7 during the reaction.
Assertion (A) The decomposition of hydrogen peroxide to form water and oxygen is an example of disproportionation reaction.
Reason (R) The oxygen of peroxide is in -1 oxidation state and it is converted to zero oxidation state in $\mathrm{O}_2$ and -2 oxidation state in $\mathrm{H}_2 \mathrm{O}$.