When compared to the diffusion of the same concentration of pure xylene cyanol, does the precence of a second solute in the mixture affect eh diffusion rate of xylend cyanol? what does this tell you about the mechanism of diffusion?

Rate of diffusion depends on many factors like

In this case the diffusion rate of xylene cyanol is not affected by the presence of other solute in the mixture unless it is affecting any property of the mixture like density.  

Also, the mechanism of diffusion involves only the concentration changes of a particular substance in the solution medium.

2h2o2--> 2h2o + o2

this reaction is of the spontaneous decomposition of hydrogen peroxide down into water and oxygen.

add 2 molecules of hydrogen peroxide and 2 molecules of water. since oxygen is naturally diatomic, the total number of atoms of each element is now the same on both sides of the equation so it is balanced.

this may not be entirely correct but let me know.