How many moles of MgCl2 are produced from 4 moles of HCl

2 moles of MgCl2.

Explanation:

We'll begin by writing the balanced equation for the reaction. This is given below:

Mg + 2HCl —> MgCl2 + H2

Now, we can determine the number of mole MgCl2 produced from 4 moles of HCl as follow:

From the balanced equation above,

2 moles of HCl reacted to produce 1 mole of MgCl2.

Therefore, 4 moles of HCl will react to produce = (4 x 1)/2 = 2 moles of MgCl2.

Therefore, 2 moles of MgCl2 were produced from the reaction of 4 moles of HCl.