What is the minimum volume of 5.0 M HCl required to completely dissolve 10.0 g of magnesium metal?
Solution 91P :
Molarity of HCl(Hydrochloric acid) = 5.0 M
Amount of Mg metal = 10.0 g
Volume of HCl to completely dissolve Mg = ?
Let’s write the chemical equation for the given scenario :
Mg(s) + 2HCl → MgCl2 + H2(g)
From the above reaction, we see the ratio of reactants is 1 : 2.
Now, let’s find the number of moles of Mg and HCl :
Number of moles(n) =
Molar mass of Mg = 24.305 g/mol.
Therefore, n =
= 0.411 moles.
We are not given the mass of HCl, but from the reaction, we know that the ratio of Mg and HCl is 1 : 2. Hence, we calculate the moles of HCl as :
= 0.411 2
= 0.822 moles.