Question

12 gram of magnesium react with dilute mineral acid to produce maximum hydrogen equal to

Answer 1

Since the dilute mineral acid is not given, we will use the hydrogen ions:

Equation:

Mg + 2H^+ ----->  Mg (ions)  + H2

(s)     (aq)            (s/aq)          (g)

ratio of moles of Mg: H2 =  1:1

moles of magnesium ions:  moles= mass/molar mass

                                                     12/24  =0.5 moles

if ratio = 1:1 then moles of hydrogen gas produced = 0.5 moles

The question requires amount of hydrogen gas:

Mass= moles x molar mass

       = 0.5 x 2  =1 g

Therefore 1 g of hydrogen gas is produced.