The answer is 155 pm, hope this helps!
FBI Fedral Burea of Investagation
do you have anymore numbers to add to this problem??
Solution :
Molar mass of 
is :
M = 6×12 + 6×1 g
M = 78 g
78 gram of contains 
molecules.
So, 89.5 gram of contains :
Now, from the formula we can see that one molecule of contains 2 hydrogen atom . So, number of hydrogen atom are :
Hence, this is the required solution.
Solution here,
Volume(V)=67.4 L
Pressure(P)=1 atm
Temperature(T)=(0+273)K=273K
Universal gas constant(R)=0.0821 L.atm.mol^-1K^-1
No. of moles(n)=?
Now,
PV=nRT
or, 1×67.4=n×0.0821×273
or, 67.4=22.4n
or, n=67.4/22.4
or, n=3
therefore, required no. of mole is 3.
