For all academic study it is helpful to have the big picture before looking at the specifics. This introduction is a must for this objective.

Hydrocarbons are compounds made from hydrogen and carbon. The first observation in Organic Chemistry is; the chemical reactions of the molecule are dependent on the type of bonds present in the molecule. So for systematic study we classified hydrocarbons according to the type of bonds present in the compound.

Hydrocarbons with only CC σ-bonds are known as alkanes. Those with at least one CC π-bond will be known as alkenes, and those with at least one CC δ-bond as alkynes.

Before we can discuss the chemistry of hydrocarbons we must recognise a compound by its name. Or be able to name a compound so that others can know what compound we are referring to. We have common names used by the general public especially those in the chemical industry. They are basically the historical names or trade names for the compounds. This serves its purpose for those who are in the know as it is not systematic. Chemists has to deal with a large variety of compounds and it will not be possible to try to remember them in isolation, or catch up with the name of newly prepared compounds. We need a system so that even if a chemist is not familiar with a compound he knows what it is by its name. The system for naming compounds is known as nomenclature.

In 1982, forty chemists met at Geneva in an "International Congress of Chemists" to set up a systematic approach in naming compounds. It eventually became the present "International Union of Pure and Applied Chemistry (IUPAC)". One of the objectives of IUPAC is to make all chemists understand one another in chemistry terminologies, including the names of compounds. So when new compounds are prepared chemists will use the nomenclature developed by IUPAC. As for the more common and very well established compounds we may still refer to them by their common names.

Beside the IUPAC nomenclature there may be other nomenclatures developed by other organizations. This are not so well accepted except when it is more user friendly as compared to the IUPAC nomenclature.

The physical properties of hydrocarbon is very much dependent on the size of the hydrocarbon, since this will determine the amount of interaction between the molecules. Other consideration will be the configuration of the molecule, that is the manner the various components are attached onto each of the carbon centre. The CC π-bond introduces another dimension to the configuration of molecule as it is a rigid bond. So the same components can be attached to carbons in various positions to give cousin compounds known as stereoisomers.

The chemistry of alkanes are comparative easy. The only significant subclassification is between alkanes in the form of a chain or a ring. The latter are known as cycloalkanes.

As we proceed to alkenes we are faced with compounds with more than one CC π-bond. Since we need only the presence of one CC π-bond to qualify the hydrocarbon as an alkene, those with more than one CC π-bond are also known as alkenes. However we discovered that the chemistry can be rather different depending on the manner the CC π-bonds are arranged relative to each other. The simplest illustration is the dienes.

When the multiple CC π-bonds in a cycloalkene are arranged in a certain order the chemistry can be so very different that we have to classified them differently. They became known the aromatics.

Before we proceed further it is appropriate to know that petroleum is the main raw material for hydrocarbons, and consequently for all the other organic compounds.

Common sense tells us that hydrocarbons can be activated for chemical reactions if a carbon in the molecule has only seven valence electron. Meaning one valence electron of the carbon has yet to find a partner. Such hydrocarbons are known as free radicals. Another possibility is when one carbon is robbed of one electron, carbonium ion. In both cases the carbon will seek to restore its octet valence electron shell. The third possibility is when a carbon stole an electron. This carbanion with a lone-pair of electron on the carbon instantly becomes a target for attack. Since all these species are not stable, the chemistry of hydrocarbon is about how to generate these three species and how these species play out to restore the stability of the particular carbon in the hydrocarbon.

It is not surprising that solvents has a effect on the chemistry of hydrocarbon if it involves charged species like the positively charged carbonium ion and the negatively charged carbanion ion.

To widen the application of hydrocarbons we add other elements into the compound. The most common will be the halogens, oxygen and nitrogen. So we prepare the alkyl halides, alcohols, ethers and amines. All these groups exhibit one similar reaction. They can be replaced by each other or be removed by a Nucleophilic Substitution Reaction or an Elimination Reaction respectively, under the correct condition. Of course each also has its own distinct chemistry.