Haemoglobin contain `0.33%` or iron by weight. The molecular weight of haemoglobin is approximately 67200. The number of iron atoms. (At wt of Fe=56) present in one molecule of haemoglobin is

Options

A. 6
B. 1
C. 4
D. 2

Explanation

To find the number of iron atoms present in one molecule of hemoglobin, we can follow these steps:

### Step 1: Calculate the mass of iron in one molecule of hemoglobin.
Given that hemoglobin contains 0.33% iron by weight, we first need to find the mass of iron in one molecule of hemoglobin.

\[ \text{Mass of iron} = \frac{0.33}{100} \times \text{Molecular weight of hemoglobin} \]
\[ \text{Mass of iron} = \frac{0.33}{100} \times 67200 = 221.76 \text{ g/mol} \]

### Step 2: Convert the mass of iron to moles of iron.
Next, we need to convert the mass of iron to moles using the atomic weight of iron (Fe = 56 g/mol).

\[ \text{Moles of iron} = \frac{\text{Mass of iron}}{\text{Atomic weight of iron}} = \frac{221.76}{56} \]
\[ \text{Moles of iron} \approx 3.96 \text{ mol} \]

### Step 3: Calculate the number of iron atoms.
Since one mole of any substance contains Avogadro's number of entities (atoms, molecules, etc.), we can find the number of iron atoms.

\[ \text{Number of iron atoms} = \text{Moles of iron} \times \text{Avogadro's number} \]
\[ \text{Number of iron atoms} = 3.96 \times 6.022 \times 10^{23} \text{ atoms/mol} \]

However, since we want the number of iron atoms in one molecule of hemoglobin, we can directly round the moles of iron to the nearest whole number.

\[ \text{Number of iron atoms} \approx 4 \]

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

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