posted by john .
Which of the following reactions should be fast at room temperature? Which would be slow? Explain
B. H2(g)+Cl2(g)->2 HCL(g)
I would assume that B would react faster because it has all gases.??
I think your assumption is not right. A is almost instantaneous since the aqueous solutions mix instantaneously. B reacts slower because those gases must mix before they react. In addition, Ag^+ and Cl^- are ready to form AgCl as soon as they come in contact with each other. In B, H2 must break the H-H bond, Cl2 must break the Cl-Cl bond, then H atom must collide with a Cl atom to form HCl.
so the temperature doesnt have a whole lot to do with this reaction?
Actually it does. But room temperature doesn't provide the energy to break the H-H and Cl-Cl bonds and that is the primary reason (at least one of the reasons) for the slow reaction. At higher temperatures you have a few individual atoms present and the higher the temperature the more of those individual atoms you have.