What is the maximum amount of magnesium chloride you can produce when 15 g of magnesium (mg) reacts with 20 g of hydrochloric acid (hcl)? mg + hcl → mgcl2 + h2?

 The maximum amount  of Magnesium chloride  that can be produced is  26.11 grams

   calculation
find the moles of each  reactant
that is
moles  = mass/molar mass
 moles of mg = 20 g/ 24.3 g/mol =0.617   moles
moles  of HCl =20/36.5 =0.548  moles

write a balanced  equation for reaction

Mg +2HCl  =MgCl2 +H2
by  use of  mole ratio between  Mg to MgCl2  which is 1:1  therefore the moles of MgCl2 = 0.617  moles

by use  of  mole ratio between HCl to MgCl2   which is 2:1  the moles of  MgCl2  is therefore = 0.548 x1/2=0.274  moles

HCl  is  the limiting  reagent  therefore we use the moles  MgCl2  derived  from  HCl, that is 0.274  moles

maximum mass is therefore =  moles x molar  mass
the  molar mass of MgCl2 = 24.3 +(35.5 x2) =95.3 g/mol

maximum  mass  is therefore = 0.274  x95.3  = 26.11  grams