[cheah10]

I wanna ask, I know that AgCl, AgI, PbCl2 and PbI2 are all precipitates in any solution. But then will there be any reactions if I put AgCl + PbI2 or AgI + PbCl2?

[Borek]

Do you mean if you put precipitates in water, or you just mix solids?

Not that teh final answer will be substantially different, although time required to reach the equilibrium in the solution will be many orders of magnitude shorter.

[cheah10]

I want to know what happens for both cases, thanks

[cheah10]

What happens when I mix:
1) PbI₂ solid & AgCl solid in anhydrous condition
2) PbI₂ solid & AgCl solid in water
3) PbCl₂ solid & AgI solid in anhydrous condition
4) PbCl₂ solid & AgI solid in water?

will they react? and what are the products?

[Borek]

Let me put it this way: the system with the lowest energy is the one dominated by the least soluble salt.

[cheah10]

hmm...then is the least soluble salt among the 4 salts mentioned here AgI? If it is, then is it that the equation will look like this:
PbI₂ + 2AgCl  PbCl₂ + 2AgI ?

then, is this reaction reversible or not? and most important question, how do PbI₂ & AgCl react when they don't exist as aqueous form? How do the ions collide and react?

sorry I like to ask questions haha

[Borek]

Ions diffuse even in solids, just very slowly.

[cheah10]

really? I see now. Thanks!