W(NaCl)=1.966g/58.5g/mol=0.0341mol
v(NaCl)=1.966g*2.17g/ml=4.267ml
v(H2O)=200-4.267=195.733ml/1000=0.195733 L
Cм=0.0341mol/0.195731L=0.174mol/L=0.174M
Mg + H2SO4 = MgSO4 + H2
n(H2) = n(Mg) = 2 моль
V(H2) = 2* 22,4 = 44,8 л
FeO + H2SO4 = FeSO4 + H2O
BaCl2 + H2SO4 = BaSO4 + 2РСд
Na2S + H2SO4 = Na2SO4 + H2S
8Cs + 6H2SO4 = 4Cs2SO4 + SO2 + S +6H2O