Which of the following arrangements represent increasingg oxidation number of the central atom?

Options

A. `CrO_(2)^(-),ClO_(3)^(-),CrO_(4)^(2-),MnO_(4)^(-)`
B. `ClO_(3)^(-),CrO_(4)^(2-),MnO_(4)^(-),CrO_(2)^(-)`
C. `CrO_(2)^(-),ClO_(3)^(-),MnO_(4)^(-),CrO_(4)^(2-)`
D. `CrO_(4)^(2-),MnO_(4)^(-),CrO_(2)^(-),ClO_(3)^(-)`

Answer

To determine the increasing oxidation number of the central atom in the given compounds, we will calculate the oxidation states for each compound step by step.

### Step 1: Calculate the oxidation state of Chromium in CrO2^-
Let the oxidation state of Chromium be \( X \).
- The oxidation state of Oxygen is -2.
- The formula for the overall charge is:
\[ X + 2(-2) = -1 \]
Simplifying this gives:
\[ X - 4 = -1 \implies X = +3 \]
So, the oxidation state of Chromium in CrO2^- is +3.

### Step 2: Calculate the oxidation state of Chlorine in ClO3^-
Let the oxidation state of Chlorine be \( Y \).
- The oxidation state of Oxygen is -2.
- The formula for the overall charge is:
\[ Y + 3(-2) = -1 \]
Simplifying this gives:
\[ Y - 6 = -1 \implies Y = +5 \]
So, the oxidation state of Chlorine in ClO3^- is +5.

### Step 3: Calculate the oxidation state of Chromium in CrO4^2-
Let the oxidation state of Chromium be \( Z \).
- The oxidation state of Oxygen is -2.
- The formula for the overall charge is:
\[ Z + 4(-2) = -2 \]
Simplifying this gives:
\[ Z - 8 = -2 \implies Z = +6 \]
So, the oxidation state of Chromium in CrO4^2- is +6.

### Step 4: Calculate the oxidation state of Manganese in MnO4^-
Let the oxidation state of Manganese be \( W \).
- The oxidation state of Oxygen is -2.
- The formula for the overall charge is:
\[ W + 4(-2) = -1 \]
Simplifying this gives:
\[ W - 8 = -1 \implies W = +7 \]
So, the oxidation state of Manganese in MnO4^- is +7.

### Summary of Oxidation States:
- CrO2^-: +3
- ClO3^-: +5
- CrO4^2-: +6
- MnO4^-: +7

### Final Arrangement of Oxidation States:
The increasing order of oxidation states is:
- CrO2^- (+3) < ClO3^- (+5) < CrO4^2- (+6) < MnO4^- (+7)

### Conclusion:
The arrangement that represents the increasing oxidation number of the central atom is:
**CrO2^- < ClO3^- < CrO4^2- < MnO4^-**