Practice Problem Answers

Back to Double Replacement

Write correct formulas for the products in these double replacement reactions.

1) Ca(OH)2 + H3PO4 ---> Ca3(PO4)2 + H2O

2) K2CO3 + BaCl2 ---> KCl + BaCO3

3) Cd3(PO4)2 + (NH4)2S ---> CdS + (NH4)3PO4

4) Co(OH)3 + HNO3 ---> Co(NO3)3 + H2O

5) AgNO3 + KCl ---> AgCl + KNO3

6) Na2CO3 + H2SO4 ---> Na2SO4 + CO2 + H2O

7) Al(OH)3 + HC2H3O2 ---> Al(C2H3O2)3 + H2O

8) Al2(SO4)3 + Ca3(PO4)2 ---> AlPO4 + CaSO4

9) Cr2(SO3)3 + H2SO4 ---> Cr2(SO4)3 + SO2 + H2O

10) AgC2H3O2 + K2CrO4 ---> Ag2CrO4 + KC2H3O2


Here are more examples of the decomposition into gas and water:

KOH + (NH4)2SO4 --->

(NH4)3PO4 + Mg(OH)2 --->

(NH4)2SO4 + Ca(OH)2 --->

MnO2 + HCl ---> MnCl2 + Cl2 + H2O

Actually, this last one is a bit of an oddball at this beginning level. The ChemTeam would not ask it on a test, but the other three would be fair game.