Chemistry · Biomolecules

JEE Main 2025 — 7 April, Morning Shift — Question 21

Thyroxine, the hormone has given below structure

The percentage of iodine in thyroxine is $\_\_\_\_\_$ %. (nearest integer)

(Given molar mass in $\mathrm{g} \mathrm{mol}^{-1} \mathrm{C}: 12, \mathrm{H}: 1, \mathrm{O}: 16$ , N : 14, I : 127)

Answer: 65

Numerical answer — enter this value.

$\%$ of $I=\frac{\text { mass of iodine }}{\text { mass of thyroxine }} \times 100$

=\frac{4 \times 127}{777} \times 100=65 \%

Answer key and solution verified before publishing.

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