# What is balanced reaction of magnesium with hafnium tetrachloride by the Kroll Process?

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You need to write the chemical equation of magnesium with hafnium tetrachloride such that:

`HfCl_4 + x*Mg = y*MgCl_2 + z*Hf`

You need to find the coefficients x,y,z, to balance the equation, such that:

- since in compund `MgCl_2` there exists 2 atoms of `Cl` , but 4 atoms enters, you need to put 2 in front of `MgCl_2` , to the right, hence `y = 2` , such that:

`HfCl_4 + x*Mg = 2*MgCl_2 + z*Hf`

- since in `2*MgCl_2` there exists 2 atoms of `Mg` , you need to put 2 in front of reactant `Mg` , to the left, hence, `x = 2` , such that:

`HfCl_4 + 2*Mg = 2*MgCl_2 + z*Hf`

- since 1 atom Hf enters, then `z = 1` .

**Hence, evaluating the balanced chemical equation that produces hafnium by Kroll process, yields **`HfCl_4 + 2*Mg = 2*MgCl_2 + Hf.`