Ca + 2HCl = CaCl₂ + H₂
m(Ca)=60 g
c=1.25 mol/l
M(Ca)=40g/mol
v-?
m(Ca)/M(Ca)=m(HCl)/[2M(HCl)]=n(HCl)/2
n(HCl)=2m(Ca)/M(Ca)
n(HCl)=cv
cv=2m(Ca)/M(Ca)
v=2m(Ca)/{cM(Ca)}
v=2·60g/mol/{1.25mol/l·40g/mol}=2.4 l = 2400 ml
2400 milliliters of a 1.25 molar HCl solution would be needed