中四chem(1)

PbCl2 (insoluble salt = by precipitation)
so we can use Pb(NO3)2 solution (lead(II) nitrate) and NaCl solution (sodium chloride)
Pb(NO3)2 (aq) + 2NaCl (aq) --> PbCl2(s) + 2NaNO3(aq)

MgCO3 (insoluble salt = by precipitation)
so we can use NaHC03 solution (sodium hydrogencarbonate) and MgCl2 solution (magnesium chloride)
2NaHCO3(aq) + MgCl2 (aq) --> MgCO3(s) + 2NaCl(aq) + CO2(g) + H2O(l)

K2SO4 (soluble salt = by neutralization)
so we can use H2SO4 (sulphuric acid) and KOH solution (potassium hydroxide)
H2S04(aq) + 2KOH(aq) --> K2SO4(aq) + 2H2O(l)

ZnSO4 (soluble salt = by neutralization)
so we can use excess ZnO (zinc oxide) and H2SO4 (sulphuric acid)
ZnO(s) + H2SO4(aq) --> ZnSO4(aq) + H2O(l)

希望可以幫到你啦~ ; )