The first step is to use the molecular weight of HCl to convert 145g to moles of HCl (mw=36.458g/mol):
[tex]145g\cdot\frac{mol}{36.458g}=3.97mol[/tex]Now, use the ratio of the coefficients of MnCl2 to HCl, to find how many moles of MnCl2 are produced with this amount of HCl:
[tex]3.97molHCl\cdot\frac{1molMnCl_2}{4molHCl}=0.9925molMnCl_2[/tex]Use the molecular weight of MnCl2 to convert the amount of moles produced to grams:
[tex]0.9925molMnCl_2\cdot\frac{125.844g}{molMnCl_2}=124.9g[/tex]124.9g of MnCl2 are produced.
