I believe that the best answer among the choices provided by the question is
<span>D.[HI] in experiment A equals 1/2[I2] in experiment B.</span>
Hope my answer would be a great help for you. If you have more questions feel free to ask here at Brainly.
You are going to fall, face first on the ground.
Answer: 
atoms of hydrogen are there in
35.0 grams of hydrogen gas.
Explanation:
According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP and contains avogadro's number 
of particles.
To calculate the moles, we use the equation:
1 mole of hydrogen 
= 
atoms
17.5 mole of hydrogen = 
atoms
There are atoms of hydrogen are there in
35.0 grams of hydrogen gas.
Ummm I think it is C. ( not sure)
Reactants on the left and products on the right
