This is the reaction which involves PbCl2 and FeCl3

Pb(NO3)2 + FeCl3 → Fe(NO3)3 + PbCl2 + Heat

Balancing the reaction ...

3Pb(NO3)2 + **2**FeCl3 → 2Fe(NO3)3 + **3**PbCl2 + Heat

Therefore FeCl3 and PbCl2 are in **2:3** ratio.

That means ...

2 moles of FeCl3 react with 2 moles of Pb(NO3)2 to form 2 moles of Fe(NO3)3 and 3 moles of PbCl2.

NOTE:- Just refer the stoichiometric coefficient from the reaction which will give you the mole ratio.

You should remember that you need to balance the equation that involves the compounds `FeCl_3` and `PbCl_2` to find out the coefficients needed.

You need to identify the equation that involves the given compounds such that:

`Pb(NO_3)_2 + FeCl_3 -gt PbCl_2 + Fe(NO_3)_3`

You should start to balance `(NO_3)` group. Notice that you need to multiply by 3 to the left and by 2 to the right such that:

`3Pb(NO_3)_2 + FeCl_3 -gt PbCl_2 + 2Fe(NO_3)_3`

You need to balance Pb, hence, you should multiply by 3 to the right such that:

`3Pb(NO_3)_2 + FeCl_3 -gt 3PbCl_2 + 2Fe(NO_3)_3`

You need to balance Fe and Cl, hence, you need to multiply by 2 to the left such that:

`3Pb(NO_3)_2 + 2FeCl_3 -gt 3PbCl_2 + 2Fe(NO_3)_3`

**Hence, evaluating the complete balanced equation yields `3Pb(NO_3)_2 + 2FeCl_3 -gt 3PbCl_2 + 2Fe(NO_3)_3` and the mole ratio of `FeCl_3 ` to `PbCl_2` is of `2:3` .**