Chemistry Multiple Choice Question

Equal masses of the metals Na, Mg, Ca and Ag are added to separate samples of excess HCl (aq) which metal produces the greatest total volume of H2 (g) [hydrogen gas]

a) Na
b) Mg
c) Ca
d) Ag

and please explain why?
thankyou 10 points for best explanation!

lets m be the mass of the metals .

the number of moles are m/mass of metals . in these metals Na and Ag are monovalent so they produce only 1 mole of H and 0.5 moles of H2 by mole of metal
Na has a molar mass of 23 so Na+HCl--> NaCl+ 0.5H2
and you produce 0.5*m/23moles of H2=0.022*molesof H2


Same holds for Ag but its molar mass is 108 and you produce 0.5m/108=0.0046moles of H2

For Mg which is divalent Mg +2HCl-->MgCl2+H2 you have since molar mass of Mg is 24 you will have m/24=0.041moles of H2
same holds for Ca (molar mass 40) so you produce m/40=0.025moles of H2

So correst answer is answer b Mg

Na because Na is the mmost reactive metal in the above four metals...........there fore it displaces more volume of hydrogen.......

(a) Na
sodium ismost reactive metal so it is the right answer