I believe we are
choosing between HBr, NO2, and C2H6.
The molar masses of
these compound are:
Molar mass of HBr =
80.9119
Molar mass of NO2 = 46.005
Molar mass of C2H6 = 30.0694
The speed of the molecule actually is inversely proportional
to its molar mass. Hence, the lighter the molecule, the faster it moves.
Answer:
C2H6 (ethane)
