Which statement best describes the density and rate of effusion of the following gases?
NO₂, C₂H₆, Kr, Xe, F
a. Fluorine has the lowest density and the lowest rate of effusion
b. Krypton has the lowest density and greatest rate of effusion Xenon has the greatest rate of effusion and the lowest density
c. Ethane has the greatest rate of effusion and the lowest density
d. Nitrogen dioxide has the highest density and the greatest rate of effusion