Question

Calculate the no. of iron atoms present in one molecule of haemoglobin given that haemoglobin contains $0.33\%$ of iron by weight. the molecular weight of it is approx.$67200$

• A. $1$
• B. $2$
• C. $4$
• D. $6$

Answer 1

The correct option is C

$4$

Explanation for correct option:

Option (C) $4$

Step 1: Analyze given data

Percentage of Iron ($\mathrm{Fe}$) present in Haemoglobin $=0.33\%$

Molecular weight $=67200\mathrm{g}{\mathrm{mol}}^{-1}$

Step 2: Find the weight of Iron

Weight of iron present

$$\begin{gathered} =\frac{0.33}{100}\times 67200 \\ =221.8\mathrm{g}{\mathrm{mol}}^{-1} \end{gathered}$$

Step 3: Find moles of Iron

The atomic weight of iron$=55.845\mathrm{g}{\mathrm{mol}}^{-1}$

Therefore the number of moles of iron $=\frac{221.76}{55.845}=3.97\approx 4$

So, the number of iron atoms present in one molecule of hemoglobin is $4$. Hence, option (C) is the correct one.