9. $3MgCl_{2} + 2H_{3}PO_{4} → Mg_{3}(PO_{4})_{2}↓ + 6HCl$
10. $CaCO_{3} + 2HCl → CaCl_{2} + H_{2}O+CO_{2}↑$
11. $FeS + 2HCl → FeCl_{2} + H_{2}S↑$
12. $FeCl_{3} + 3NaOH →3NaCl + Fe(OH)_{3}$
13. $Al_{2}(SO_{4})_{3} + 6KOH → 3K_{2}SO_{4} + 2Al(OH)_{3}↓$
14. $CaSO_{3} + 2HNO3 → Ca(NO_{3})_{2} + H_{2}O+SO_{2}↑$
15. $K_{2}CO_{3} + Ca(OH)_{2} → 2KOH + CaCO_{3}↓ $
16. $Pb(NO_{3})_{2} + Zn → Zn(NO_{3})_{2} + Pb↓$
17. $2Al(OH)_{3} + 3H_{2}SO_{4} → Al_{2}(SO_{4})_{3} + 6H_{2}O$
18. $Fe(OH)_{3} + 3HCl → FeCl_{3} + 3H_{2}O$
19. $FeCl_{3}+ 3KOH → Fe(OH)_{3}↓ + 3KCl$
20. $CuSO_{4} + 2NaOH → Cu(OH)_{2}↓ + Na_{2}SO_{4}$
