A 400 mg iron capsule contains 100 mg of ferrous fumarate, `(CHCOO)_(2)`Fe. The percentage of iron present in it is approximately

Options

A. (a)33%
B. (b)25%
C. (c )14%
D. (d)8%

Explanation

To find the percentage of iron present in a 400 mg iron capsule that contains 100 mg of ferrous fumarate, we can follow these steps:

### Step 1: Determine the molar mass of ferrous fumarate \((CHCOO)_2Fe\)

1. **Calculate the molar mass of each component:**
- Carbon (C): 12 g/mol
- Hydrogen (H): 1 g/mol
- Oxygen (O): 16 g/mol
- Iron (Fe): 56 g/mol

2. **Calculate the molar mass of ferrous fumarate:**
- Ferrous fumarate has the formula \((CHCOO)_2Fe\), which consists of:
- 4 Carbon atoms: \(4 \times 12 = 48\) g/mol
- 4 Hydrogen atoms: \(4 \times 1 = 4\) g/mol
- 4 Oxygen atoms: \(4 \times 16 = 64\) g/mol
- 1 Iron atom: \(1 \times 56 = 56\) g/mol

\[ \text{Total molar mass} = 48 + 4 + 64 + 56 = 172 \text{ g/mol} \]

### Step 2: Calculate the amount of iron in 100 mg of ferrous fumarate

1. **Determine the fraction of iron in ferrous fumarate:**
- From the molar mass, we know that 172 g of ferrous fumarate contains 56 g of iron.

2. **Calculate the amount of iron in 100 mg of ferrous fumarate:**
\[ \text{Iron in 100 mg} = \left(\frac{56 \text{ g}}{172 \text{ g}}\right) \times 100 \text{ mg} \]
\[ = \left(\frac{56}{172}\right) \times 100 \approx 32.56 \text{ mg} \]

### Step 3: Calculate the percentage of iron in the iron capsule

1. **Use the total weight of the capsule to find the percentage:**
\[ \text{Percentage of iron} = \left(\frac{32.56 \text{ mg}}{400 \text{ mg}}\right) \times 100 \]
\[ = \left(\frac{32.56}{400}\right) \times 100 \approx 8.14\% \]

### Final Answer
The percentage of iron present in the iron capsule is approximately **8.14%**.

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