<span>BaCl</span>2<span> + Na</span>2<span>SO</span>4<span> = BaSO</span>4 <span>↓ + 2NaCl </span>
<span>NaOH + HCl = NaCl + H<span>2</span>O (не знаю, думаю так)</span>
BaCl2 + ZnSO3 = BaSO3↓ + ZnCl2
KCl + AgNO3 = KNO3 + AgCl
HCl + KCO3 = CO2 + H2O + KCl
MgCl2 + 2AgNO3 = 2AgCl + Mg(NO3)2
--------------------------
Fe2(SO4)3 = 2Fe(3+) + 3SO4(2-)
n(Fe2(SO4)3) : n(SO4(2-)) = 1 : 3, следовательно, n(Fe2(SO4)3) = n(SO4(2-)) / 3 = 1,8 моль / 3 = 0,6 моль