1. Predicting Reaction Products - Question 4
David Lee
Retired AP Chemistry Teacher
35 years at Mountain Lakes HS
5/23/2019

2. Classification of Reactions
Acid/Base
Precipitation
Hydrolysis
Decomposition (& reversed)
Ligands Today’s lesson
REDOX
Organic
May 22, 2004
Predicting Reaction Products

3. Scoring the question
The student is given 1 point for the correct chemical formula for the reactants.
Two points for the correct chemical formula for the products.
One additional point for the correct answer to the question about the reaction.
May 22, 2004
Predicting Reaction Products

4. Ligand Reactions
Ligand reactions involve the reaction between ligands and some metal anions (Fe, Cu, Pb, Ag, Au, Sn, Pt, Co, etc).
Learn the common ligands: CN-, SCN-, NO2- , NH3, H2O, OH-, halides (F-, Cl-, Br-, I-)
May 22, 2004
Predicting Reaction Products

5. Ligands
In coordination chemistry a ligand is an ion or molecule that binds to a central metal atom to form a coordination complex.
The bonding between metal and ligand generally involves formal donation of one or more of the ligand's electron pairs.
May 22, 2004
Predicting Reaction Products

6. Ligands Ligands are viewed as Lewis Bases.
In other words: Coordination ions are the result of a Lewis Acid-Base Reaction.
May 22, 2004
Predicting Reaction Products

7. Ligand Reactions
General rule: The number of ligands attached to the metallic cation is usually DOUBLE the cation’s charge.
Ag(NH3)2+ Cu(NH3)42+ Fe(NH3)63+ Ag Cu Fe3+
May 22, 2004
Predicting Reaction Products

9. Ligand Reactions Sample #1
2003 (e) Excess concentrated aqueous ammonia is added to solid silver chloride.
NH3 + AgCl > (1 point)
NH3 + AgCl > Ag(NH3) Cl (3 points)
May 22, 2004
Predicting Reaction Products

10. Ligand Reactions Sample #2
1989 (f) A solution of ammonium thiocyanate is added to a solution of iron(III) chloride.
NH4SCN + FeCl > (1 point)
NH4SCN + FeCl >
(NH4)3 Fe(SCN)6 + NH4Cl (2 points)
May 22, 2004
Predicting Reaction Products

11. Ligand Reactions Sample #1
SCN- + Fe > Fe(SCN)63-
(4 points)
What type of reaction is this?
A Lewis Acid-Base reaction.
May 22, 2004
Predicting Reaction Products

13. Sample Quiz for Question 4
(g) Excess sodium cyanide solution is added to a solution of silver nitrate.
Identify the Lewis Base in this reaction.
May 22, 2004
Predicting Reaction Products

14. Sample Quiz for Question 4 Answers
(g) Excess sodium cyanide solution is added to a solution of silver nitrate.
CN- + Ag > Ag(CN)2-
Ligand
Silver is the Lewis Base in this reaction. (Electron acceptor)
May 22, 2004
Predicting Reaction Products

15. Questions?
Other questions in the reaction prediction question may include: Name the product.
May 22, 2004
Predicting Reaction Products