Řešení

m(Zn) = 1 g

M(Zn) = 65,39 g/mol

m(HCl) = ?

M (HCl) = 36,46 g/mol

ρ(HCl, 20%) = 1,098 g.cm^-3

Zn  +  2 HCl  ―›  ZnCl₂ +  H₂ 

m(HCl) = 1,1 g 100%

x g  …………...100% (HCl)

1,1g …………...20% (HCl)

x = 1,1*100/20 = 5,5 g

V = m/ρ

V(HCl) = 5 cm³ 20%