Given the reaction, H2 + Cl2 Imported Asset 2HCl, if 12.0 moles of HCl were made, then how many moles of H2 were used

Question

Given the reaction, H2 + Cl2   Imported Asset  2HCl, if 12.0 moles of HCl were made, then how many moles of H2 were used

anonymous · Answer

The balanced equation is        $H_2~~~~~~+~~~~~~Cl_2~~~~~~\rightarrow~~~~~~~2HCl$.
                                            1 mole                                       2 mole
                                            x mole                                      12 mole

If we use 1 mole of $H_2$, 2 moles of $HCl$ will be formed. Then if 12.0 moles of $HCl$ are formed, then how many moles of $H_2$ were used?

I summarized the problem as above. Can you solve it?