1. Organic Reactions

2. Major Terminology Associated with Organic Reactions
Substrate…organic reactant being modified by the reagent.
2. Reagent…inorganic or organic reactant that modifies the substrate.
Solvent…medium that dissolves the reactants.
Catalyst…substance that reduces the amount of energy needed to start a reaction but is not part of the reaction.
Condition…the physical or physicochemical quantity used in the reaction.

3. A Single Step Chemical Equation

4. Example of a Single Step Chemical Eqn.

5. Addition Reactions
Double and triple bonds are weaker than single bonds
More reactive
In the addition reaction, reactants are added to the carbon atoms in the double or triple bond.

6. Addition Reactions

7. Addition Reactions
H2C=CH2 + A—B  H2C—CH2
A B

8. Hydrogenation
In hydrogenation, hydrogen atoms add to the carbon atoms of a double bond or triple bond.
A catalyst such as Pt or Ni is used to speed up the reaction.

9. Hydrogenation of Oils
When hydrogen adds to the double bonds in vegetable oils, the products are solids at room temperature.

10. Halogenation
In halogenation, halogen atoms add to the carbon atoms of a double bond or triple bond.

11. Testing for Double and Triple Bonds
When bromine (Br2) is added to an alkane, the red color of bromine persists.
When bromine (Br2) is added to an alkene or alkyne, the red color of bromine disappears immediately.

12. Hydrohalogenation
In hydrohalogenation, the atoms of a hydrogen halide add to the carbon atoms of a double bond or triple bond.

13. Markovnikov’s Rule
When an unsymmetrical alkene undergoes hydrohalogenation, the H in HX adds to the carbon in the double bond that has the greater number of H.

14. Hydration Adds Water
In hydration, H and OH from water add to the carbon atoms of a double bond or triple bond to form alcohols (OH).
The reaction is catalyzed by acid H+.

15. Elimination Reactions

16. In an elimination reaction, two groups X and Y are removed from a starting material.
Two  bonds are broken, and a  bond is formed between adjacent atoms.
The most common examples of elimination occur when X = H and Y is a heteroatom more electronegative than carbon.

17. Elimination is the opposite of addition .

18. Substitution Reactions

19. Substitution reactions involve  bonds: one  bond breaks and another forms at the same carbon atom.
The most common examples of substitution occur when Z is a hydrogen or a heteroatom that is more electronegative than carbon.

20. Practice Exercises
Classify the following reactions as substitution, elimination, or addition.

21. Bond Dissociation Energy

22. Bond Dissociation Energy

24. Stronger bonds have a higher ΔHº

25. Calculating ΔHº Using Bond Dissociation Energy

26. Which has the higher bond dissociation energy?
H-Cl or H-Br b) c)