Predicting whther double displacement reactions will take place...?

Question

Using three criteria for double displacement reactions, together with a solubility table, predict whether a double displacement reaction will occur in each example.

a. K2S + CuSO4
b. NH4OH + H2C2O4
c. KOH + NH4Cl
d. NaC2H3O2 + HCl
e. Na2CrO4 + Pb(C2H3O2)2
f. (NH4)2SOH4 + NaCl
g. BiCl3 + NaOH
h. KC2H3O2 + CoSO4
i. Na2CO3 + HNO3
j. ZnBr2 + K3PO4

Answer 1

the 3 criteria I assume you are referring to are
1) formation of a precipitate (insoluble solid)
2) formation of a gas - like CO2 or H2S
3) formation of a molecule like H2O or a weak acid like HF

IF none of the 3 above happen, then the reaction does NOT take place

a. K2S + CuSO4 --> CuS + K2SO4 (CuS is insoluble)
b. 2 NH4OH + H2C2O4 --> 2 H2O + (NH4)2C2O4
c. KOH + NH4Cl --> no reaction
d. NaC2H3O2 + HCl --> HC2H3O2 + NaCl (HC2H3O2 is a molecule)
e. Na2CrO4 + Pb(C2H3O2)2 --> PbCrO4 + 2 NaC2H3O2 (PbCrO4 is insoluble)
f. (NH4)2SOH4 + NaCl --> no reaction
g. BiCl3 + 3 NaOH --> Bi(OH)3 + 3 NaCl (Bi(OH)3 is insoluble)
h. KC2H3O2 + CoSO4 --> no reaction
i. Na2CO3 + 2 HNO3 --> H2O + CO2 + 2 NaNO3
j. 3 ZnBr2 + 2 K3PO4 --> Zn3(PO4)2 + 6 KBr (Zn3(PO4)2 is insoluble)

Answer 2

Double Replacement reactions depend on the production of a solid (precipitate), liquid, gas, or redox. All of these will remove ions from the solution.

The first and last ions go together as a product and the middle two ions go together as the other product. Look up both products on a table of solubility. If they are insoluble, the reaction will occur. If a liquid or gas is formed the reaction will occur. If the charges of the ions change during the reaction (redox) a reaction will occur. If none of these thing happen no reaction will occur.

Answer 3

1

Answer 4

K2s Cuso4

Answer 5

properly, this is yet another one.... acid + base --> salt + water (neutralization) ex. NaOH + HCl --> NaCl + H2O and yet another occasion... NaCl + AgNO3 --> AgCl + NaNO3 (AgCl is the forged precipitate...to be attentive to which precipitates out of answer, study the solubility regulations) :)