The haemoglobin contains 0:33% iron by weight. Its molecular mass is 67200. The number of iron atoms in one molecule of haemoglobin are (At. mass of Fe-56)

Options

A. 2
B. 3
C. 4
D. 5

Explanation

To solve the problem of determining the number of iron atoms in one molecule of hemoglobin, we can follow these steps:

### Step-by-Step Solution:

1. **Determine the weight of iron in one molecule of hemoglobin**:
- Given that hemoglobin contains 0.33% iron by weight, we can calculate the weight of iron in one molecule of hemoglobin using its molecular mass.
- The molecular mass of hemoglobin = 67200 g/mol.
- Weight of iron in hemoglobin = (0.33/100) * 67200 g = 221.76 g.

2. **Calculate the number of moles of iron in the weight calculated**:
- We know that the atomic mass of iron (Fe) is 56 g/mol.
- To find the number of moles of iron in 221.76 g, we use the formula:
\[ \text{Number of moles of Fe} = \frac{\text{Weight of Fe}}{\text{Atomic mass of Fe}} = \frac{221.76 g}{56 g/mol} \approx 3.96 \text{ moles of Fe}. \]

3. **Determine the number of iron atoms**:
- Since 1 mole of any substance contains Avogadro's number of particles (approximately \(6.022 \times 10^{23}\) atoms), we can calculate the number of iron atoms:
- Number of iron atoms = Number of moles of Fe × Avogadro's number.
- Therefore, the number of iron atoms = \(3.96 \text{ moles} \times 6.022 \times 10^{23} \text{ atoms/mole} \approx 2.38 \times 10^{24} \text{ atoms}\).

4. **Determine the number of iron atoms per molecule of hemoglobin**:
- Since we are looking for the number of iron atoms in one molecule of hemoglobin, we can round the number of moles of iron to the nearest whole number.
- Rounding 3.96 gives us approximately 4.
- Therefore, there are approximately 4 iron atoms in one molecule of hemoglobin.

### Final Answer:
The number of iron atoms in one molecule of hemoglobin is **4**.