[Gamini]

We did following three experiments at the lab

1. NaI + FeCl3--> Fe+2  + I2

2. NaI + Cu(NO3)  --> Cu+   + I2

3. NaI + SnCl4-->  Sn2+  + I2

and observed 1st and 2nd reactions did occur and 3rd one did not.
But, according to the reduction potentials table data 2nd and 3rd reactions cannot be feasible. How can we explain 2nd one consists of experimental error?

[Hunter2]

The second one happens because the very bad solubility of CuI. The copper-I-iodide precipitates and is out of the equilibrium.