дано
m(ppaHCL) = 300 g
W(HCL) = 20 %
-------------------------
V(H2)-?
m(HCL) = m(ppa HCL) * W(HCL) / 100% = 300*20% / 100% = 60 g
Zn+2HCL-->ZlCL2+H2
M(HCL) = 36.5 g/mol
n(HCL) = m/M = 60 / 36.5 = 1.64 mol
2n(HCL) = n(H2)
n(H2) = 1.64 / 2 = 0.82 mol
V(H2) = n(H2) * Vm = 0.82 * 22.4 = 18.368 L
ответ 18.368 л