Hydrocarbons: 1 Mark
Comparison: 3 Marks
Hydrocarbons are compounds that are made up only of carbon and hydrogen atoms.
For example, ethane (C2H6), acetylene (C2H2), benzene (C6H6) etc.
Comparison of saturated and unsaturated hydrocarbons
Saturated hydrocarbonsUnsaturated hydrocarbons1. All the four valencies of each carbon atomThe valencies of at least two carbon atomsare satisfied by forming single covalentare not fully satisfied by the hydrogen atoms.bonds with carbon and hydrogen atoms.2. Carbon atoms are joined only by singleCarbon atoms are joined by double covalentcovalent bondsbonds (>C=C<) or by triple covalent⎛⎜⎝||−CC−||⎞⎟⎠bonds(−C=C−).3. They are less reactive due to the non−They are more reactive due to the presenceavailability of electrons in the singleof electrons in the double or the triple bond.covalent bond.4. They undergo substitution reactions.They undergo addition reactions.