In the following reaction, 12.0 moles of Mg(OH)2 and 16.0 moles of HCl react. Who is the limiting reactant?

The limiting reactant is HCl because you would need at least 24.0 moles of HCl for all of the Magnesium Hydroxide to react. This is because there need to be twice as many moles of HCl than there are of Magnesium Hydroxide

What does that mean you dum bum