1. Reactions in Aqueous Solution

2. Single Replacement
A lone metal, (or hydrogen or halogen) replaces another metal (or hydrogen or halogen)
AB + C → A + CB
HCl + Mg  H2 + MgCl2

3. Single Replacement
Usually results in the formation of a solid (metal) but can produce a gas (hydrogen) or a halogen

4. Single Replacement
Single replacement reactions will only proceed if the lone element is MORE ACTIVE than its counterpart in the compound Use the Activity Series of Metals (or Halogens)

5. Activity Series of Metals
Li – Lithium (most active)
K – Potassium
Ca – Calcium Li – Na will replace H from water & acids
Na – Sodium
Mg – Magnesium
Al – Aluminum
Zn – Zinc Mg – Pb will replace H from acids only
Fe – Iron
Pb – Lead
H – Hydrogen
Cu – Copper
Ag – Silver Cu and below cannot replace H at all
Au – Gold

6. Activity Series of Metals
When predicting the products of a single replacement reaction with a metal, remember the charges of the ions, and criss-cross!
EX: K + MgSO4  ???
K replaces Mg
K is +1 and SO4 is -2 so….
Mg + K2SO4 are the products

7. Activity Series of Halogens
F – Fluorine (most active)
Cl – Chlorine
Br – Bromine
I – Iodine
At – Astatine
ALL Halogens are DIATOMIC!

8. Activity Series of Halogens
*Remember* All halogens are -1 charge and diatomic when alone
EX: F2 + NaCl  ???
F will replace Cl
Na (+1) and F (-1) charge so…
Cl2 + NaF are the products

9. Single Replacements Try these: H2 + NaCl  ????? Fe + CuNO3  ?????
NO REACTION! (Na is higher than H)
Fe + CuNO3  ?????
Cu + Fe(NO3)2 (assume Fe+2)
Balance the equation…
Cl2 + MgBr2  ???
MgCl2 + Br2 (already balanced)

10. AB + CD → AD + CB Two ionic compounds react by exchanging cations
Double Replacement
Two ionic compounds react by exchanging cations
AB + CD → AD + CB
AgNO3 + NaCl → AgCl + NaNO3

11. Aqueous Solutions Many important reactions take place in water
Ionic compounds dissociate in aqueous solutions
These solutions contain free cations and anions

12. Complete Ionic Equation
An equation that shows dissolved ionic compounds as their free ions
AgNO3 (aq)+ NaCl (aq)→ AgCl (s) + NaNO3 (aq)
Ag+ + NO3- + Na+ + Cl- → AgCl (s) + Na+ + NO3-

13. Complete Ionic Equation
The equation can be simplified by eliminating ions that do not participate in the reaction.
Ions that appear on both sides of the equation can be cancelled out
These ions that are not directly involved in a reaction are called spectator ions

14. Complete Ionic Equation
AgNO3 (aq)+ NaCl (aq)→ AgCl (s) + NaNO3 (aq)
Ag+ + NO3- + Na+ + Cl- → AgCl (s) + Na+ + NO3-
Ag+ + Cl- → AgCl (s)

15. Ag+ (aq) + Cl- (aq) → AgCl (s)
Net Ionic Equation
The equation that indicates only those particles that actually take part in a reaction is the net ionic equation
Ag+ (aq) + Cl- (aq) → AgCl (s)

16. Double Replacement: Generally one of these is true:
One product is a precipitate (s).
One product is a gas (g) that bubbles out of mixture
One product is a molecular compound such as water

17. Double Replacement:
If neither product is a (s), (g) or H2O, both products will be aqueous (aq) & soluble – this means you only have a mixture and there is NO REACTION. Means you do NOT have to balance the equation b/c there is no chemical reaction taking place!

18. Double Replacement:
You can determine the solubility of a compound usually by the anion – certain anions are usually soluble (aq) (like nitrates & chlorates) & others are usually insoluble (s) (like carbonates & hydroxides)

19. Double Replacement:
Some cations can be used to determine the solubility of a compound – alkali metal (Li, Na, K) & ammonium compounds are going to be soluble with very few exceptions

20. Solubility Rules: Compounds Solubility Exceptions
. Salts of alkali metals and ammonia
Soluble
(aq)
Few exceptions
Nitrate salts and chlorate salts
Sulfate salts
Compounds of Pb, Ag, Hg, Ba, Sr, and Ca
(s)
Chloride salts
Compounds of Ag and some compounds of Hg and Pb (s)
Carbonates, phosphates, chromates, sulfides, and hydroxides
Most are insoluble
Compounds of the alkali metals and of ammonia (aq)

21. Let’s try an example: NaOH(aq) + CaCl2(aq)  ??? + ???
Na and Ca switch places, so…
Ca(OH)2 + NaCl (products)
Are either of these insoluble?
YES! Ca(OH)2 is insoluble (s)
NaOH(aq) + CaCl2(aq)  Ca(OH)2(s) + NaCl(aq)
Now balance the equation.

22. Let’s try an example:
NaOH(aq) + KCl(aq)  ??? + ??? Na and K switch places, so… KOH + NaCl (products) Are either of these insoluble? NO! Both are soluble (aq) [alkali metals] NaOH(aq) + KCl(aq)  NO REACTION

23. Let’s try an example: NaOH(aq) + HCl(aq)  ??? + ???
Na and H switch places, so…
HOH + NaCl (products)
Are either of these insoluble?
No BUT… HOH is water!!!
NaOH(aq) + HCl(aq)  HOH(l) + NaCl(aq)
Balance the equation.