Haemoglobin contains 0.33% of iron by weight. The molecular mass of haemoglobin is about 67200. The number of iron atoms (at. mass of Fe=56) present in one molecule of haemoglobin is:

Options

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

Answer

B

Explanation

Mass of 1 molecule of haemoglobin
` = (67200)/(6.022 xx 10^23)`
Mass of iron ` = (67200)/(6.022 xx 10^23) xx (0.33)/(100)`
`= 3.682 xx 10^(-22) g `
56 g of iron contains `6.02 xx 10^23` atoms ` 3.682 xx 10^(-22) g ` of iron contains
` = (6.02 xx 10^23)/(56) xx 3.682 xx 10^(-22)`
= 4 atoms