Balance the following chemical equation using the oxidation number method:

Question

K2Cr2O7 + SnCl2 + HCl → CrCl3 + SnCl4 + H2O + KCl

Answer 1

K +1 ; +1
Cr +6 ; +3 gained 3 electrons
Sn +2 ; +4 lost 2 electrons
Cl -1; -1
so the ratio of Cr to Sn is 2:3 so start out with these coefficents
K2Cr2O7 and 3SnCl2
That should get you there pretty quickly.