Question

If an iodized salt contains $1 \%$ of $KI$ and a person takes $2 \,g$ of the salt every day, the iodide ions going into his body everyday would be approx

• A. $ 7.2\times {{10}^{21}} $
• B. $ 7.2\times {{10}^{19}} $
• C. $ 3.6\times {{10}^{21}} $
• D. $ 9.5\times {{10}^{19}} $

Answer 1

Answer: (B)

$2\, g$ of the salt will contain
$K I=\frac{2}{100} g=0.02\, g$
$=\frac{0.02}{39+127} \,mol$
$=1.2 \times 10^{-4} $ mol $K I$
$=1.2 \times 10^{-4}$ mol $I ^{-}$ions
$=\left(1.2 \times 10^{-4}\right)\left(6.02 \times 10^{-23}\right) I^{-}$ions
$=7.2 \times 10^{19} I^{-}$ions