H2 <span>because the smaller the gas molecule, the faster the diffusion. (the lightest molecule will diffuse the quickest)</span>
Always. You never know what kind of chemical you’re dealing with and how powerful it is.
Increasing the concentration of one or more reactants will often increase the rate of reaction. This occurs because a higher concentration of a reactant will lead to more collisions of that reactant in a specific time period.
Reaction rate increases with concentration, as described by the rate law and explained by collision theory. As reactant concentration increases, the frequency of collision increases. The rate of gaseous reactions increases with pressure, which is, in fact, equivalent to an increase in concentration of the gas.
