The first step is to use the molecular weight of HCl to convert 145g to moles of HCl (mw=36.458g/mol):
![145g\cdot(mol)/(36.458g)=3.97mol](https://img.qammunity.org/2023/formulas/chemistry/college/t3llgmc3l6k0m0ceaffj2vcrfz8gsbcimj.png)
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:
![3.97molHCl\cdot(1molMnCl_2)/(4molHCl)=0.9925molMnCl_2](https://img.qammunity.org/2023/formulas/chemistry/college/me1nipekjnez2x7om02yg738t7v4mdvb9x.png)
Use the molecular weight of MnCl2 to convert the amount of moles produced to grams:
![0.9925molMnCl_2\cdot(125.844g)/(molMnCl_2)=124.9g](https://img.qammunity.org/2023/formulas/chemistry/college/nw5ybaq7txdwy1187d9vh24x5u51yts2jm.png)
124.9g of MnCl2 are produced.