In maxwells distribution of molecular speeds curve, how do i compare 2 gases with different molecular masses at same temperature? An example is as follows:-

At same temperature and lower speed, fraction of molecules of so2 will be greater than o2?

Maxwell distribution of molecular speed curve is based on the distribution of speed at different temperature.As th temperature rises the fraction of molecule having the most probable velocity decrease.
The most probable velocity is given by
p(c)dc=dN/N=4pi(M/2piRT)^3/2c^2e(-M/2RT)dc
thus as can be seen the fraction depends on the M the molar mass
now ,molar mass of SO2>molar mass of O2
Thus using the above formula you can compare two gases at same temperature and speed.