| Alkanes | Alkenes | Alkynes |
|---|---|---|---|
Bond type | Class of organic compounds made of only carbon and hydrogen atoms (hydrocarbon), linked using a single covalent bond.
| Class of hydrocarbon compounds with at least one carbon-carbon double covalent bond. | Class of hydrocarbons containing carbon atoms held in a triple covalent bond. |
Class of Hydrocarbon | Saturated | Unsaturated with loss of two hydrogens
| Unsaturated with loss of four hydrogens.
|
General Molecular Formula | CnH2n+2 Example, two-carbon ethane (C2H6) | CnH2n Example, two-carbon ethene (C2H4) | CnH2n-2 Example, two-carbon ethyne (C2H2) |
IUPAC name (suffix used)
| Alkane (-ane) For example, methane (one carbon), ethane (2 carbon) | Alkene (-ene) For example, ethene (2 carbon), propene (3 carbon) | Alkyne (-yne) For example, ethyne (2 carbon), propyne (3 carbon) |
Type of bond | Sigma bond | One sigma bond and one pie bond
| One sigma bond and two pie bonds |
Hybridization | The single-bonded carbons are sp3 hybridized. C-C (sp3-sp3) | The double-bonded carbons of alkenes are sp2 hybridized. C=C (sp2-sp2) | The double-bonded carbons of alkynes are sp hybridized. C≡C (sp-sp) |
Bond Length | 1.54 Ao (C-C) | 1.33 Ao (C=C) | 1.20 Ao (C≡C) |
Bond Strength | 347 kJ/mol | 611 kJ/mol | 839 kJ/mol |
Bond Angle | 108.9o | 120o | 180o |
Lowry Bronsted Acid (donation of H+) | Poor acid (pKa 50) | Weakly acidic (pKa 44) | Comparatively stronger acid (pKa 25). Only terminal alkyne is much more acidic; internal alkyne is unreactive. |
Lewis Base (donation of electrons) | Poor base | The electron-dense pie bond is basic. | The electron-dense pie bond is basic. |
Functional group | None | The carbon-carbon bond is relatively reactive therefore, it is considered a functional group. | The carbon-carbon bond is reactive; therefore, it is considered a functional group. |
Electrophile or a Nucleophile | Poor electrophiles or nucleophiles. | Can act as a nucleophile in reactions due to electron-dense pie bond. | Pie bond acts as a nucleophile in reactions. Terminal alkynes post proton abstraction are excellent nucleophiles and strong bases. |
Isomerism shown | Chain Isomerism (Structural isomerism) | -Chain and Positional Isomerism (Structural isomerism) -Cis-trans Isomerism (Stereoisomerism) | -Chain and Positional Isomerism (Structural isomerism) -Cis-trans Isomerism (Stereoisomerism) |
Types of reactions it undergoes | Least reactive class of compounds due to the absence of any functional groups or heteroatoms (atoms other than carbon and hydrogen). However, undergoes uncontrolled free radical halogenation in UV light and, combustion, and catalytic cracking at high temperatures. | Electron-rich pie bond can act as nucleophile and can undergo addition reaction with an electrophile. Polymerization and Oxidation of alkenes are other reactions. | Electron-rich pie bond can act as nucleophile and can undergo addition reaction with an electrophile. The acetylide ion is a strong base and a powerful nucleophile. It can undergo substitution reactions. Other reactions are oxidation and polymerization reactions. |
Related Reading: Introductory Organic Chemistry