1003170802

The acidity of a substance is measured by its \( pH \) value. In practice, \( pH \) is often assumed to be the negative logarithm of the hydrogen ion concentration \( H^+ \) (i.e. the number of moles of hydrogen ions per liter of solution): \[ pH = -\log{(H^+ )}. \] If an apple juice has a \( pH \) of \( 3.8 \) and a grapefruit juice has a \( pH \) of \( 3.6 \) then the hydrogen ion concentration (\( \mathrm{mol}/\mathrm{l} \)) in the apple juice is how much less than in the grapefruit juice? Round the result to six decimal places.