SnCl2+2FeCl3=SnCl4+2FeCl2
Writing the oxidation numbers on various atoms,
+2Sn−1Cl2++32Fe−1Cl3=+4Sn−1Cl4++22Fe−1Cl2
Ox. no. of Sn changes from +2 to +4, i.e., increase in oxidation number. SnCl2 is thus oxidised or it acts as a reducing agent.
Ox. no. of Fe changes from +3 to +2, i.e., decrease in oxidation number. FeCl3 is thus reduced or it acts as an oxidising agent.