In which of the following compounds, iron has an oxidation number of `+3` ?

Options

A. `Fe(NO_(3))_(2)`
B. `FeC_(2)O_(4)`
C. `FeCl_(3)`
D. None of these

Explanation

To determine in which of the given compounds iron has an oxidation number of +3, we will analyze each compound step by step.

### Step 1: Identify the compounds
The compounds we need to analyze are:
1. Fe(NO3)2
2. FeC2O4
3. FeCl3

### Step 2: Calculate the oxidation number of iron in each compound

#### Compound 1: Fe(NO3)2
- The oxidation state of nitrate (NO3) is -1.
- Since there are 2 nitrate ions, the total contribution from nitrate is:
\[ 2 \times (-1) = -2 \]
- Let the oxidation state of iron (Fe) be \( x \).
- The compound is neutral, so:
\[ x + (-2) = 0 \]
\[ x - 2 = 0 \]
\[ x = +2 \]
- Therefore, the oxidation number of iron in Fe(NO3)2 is +2.

#### Compound 2: FeC2O4
- The oxidation state of oxalate (C2O4) is -2.
- Let the oxidation state of iron (Fe) be \( x \).
- The compound is neutral, so:
\[ x + (-2) = 0 \]
\[ x - 2 = 0 \]
\[ x = +2 \]
- Therefore, the oxidation number of iron in FeC2O4 is +2.

#### Compound 3: FeCl3
- The oxidation state of chlorine (Cl) is -1.
- Since there are 3 chlorine atoms, the total contribution from chlorine is:
\[ 3 \times (-1) = -3 \]
- Let the oxidation state of iron (Fe) be \( x \).
- The compound is neutral, so:
\[ x + (-3) = 0 \]
\[ x - 3 = 0 \]
\[ x = +3 \]
- Therefore, the oxidation number of iron in FeCl3 is +3.

### Step 3: Conclusion
Among the given compounds, the only one where iron has an oxidation number of +3 is **FeCl3**.

### Final Answer:
**FeCl3** is the compound in which iron has an oxidation number of +3.

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