Answer : The number of moles of hydrogen in 2.7 mole of caffeine are 27 moles.
Explanation : Given,
Moles of caffeine = 2.7 mole
The molecular formula of caffeine is,

In the molecule
, there are 8 moles of carbon, 10 moles of hydrogen, 4 moles of nitrogen and 2 moles of oxygen.
As, 1 mole of
contains 10 moles of hydrogen
So, 2.7 moles of
contains
moles of hydrogen
Therefore, the number of moles of hydrogen in 2.7 mole of caffeine are 27 moles.