1) The chemical equation is:
Al + CuCl2 ---> Cu + AlCl3
2) You have to balance the equation to state the coefficients:
2Al + 3CuCl2 ---> 3Cu + 2Al Cl3
3) Now the coefficients tell you the molar ratios.
2 mol Al : 3 mol CuCl2 : 3 mol Cu : 2 mol AlCl3
4) The molar ratio of CuCl2 to Al is:
3 mol Cu Cl2 / 2 mol Al = 3/2 = 1.5
