Hydrocarbons
Saturated, unsaturated and aromatic compounds containing only C and H.
Saturated aliphatic hydrocarbons are inert and identified mainly by physical properties. Unsaturated hydrocarbons (alkenes and alkynes) are more reactive (by addition and oxidation). Aromatic hydrocarbons react mainly by substitution.
Alcohols
Includes both aliphatic, aromatic, & mono- to poly-hydroxy compounds.
Most monohydroxy aliphatic alcohols are liquids; the lower members are water soluble. Polyhydric alcohols are easily soluble in water. Aromatic alcohols have a hydroxy group which is not directly joined to the aromatic ring.
Phenols
Phenols have a hydroxy group directly attached to an aromatic ring.
Most phenols are weakly acidic and solid. They react mainly by forming esters and by substitution.
Carbohydrates
Also called sugars.
Mono- and di-saccharides are usually colourless water soluble solids. They may be subdivided into reducing and nonreducing sugars.
Halogen compounds
Includes both aliphatic and aromatic types.
These halogenated hydrocarbons vary from gases to solids. Alkyl halides are generally more reactive than aryl halides.
Ethers
Generally inert.
Aliphatic ethers are almost as unreactive as aliphatic hydrocarbons. Aromatic ethers are not quite as inert and may be chemically characterised.
Aldehydes and Ketones
Often known as carbonyl compounds.
Both aldehydes and ketones have many reactions in common because of the carbonyl group. The special property of aldehydes is their ease of oxidation.
Carboxylic Acids
Includes both aliphatic and aromatic compounds.
Aliphatic acids may be liquid or solid while aromatic acids are solid. The lower members of the aliphatic series are water soluble and acidic.
Esters
Formed from a carboxylic acid and an alcohol.
Most esters are liquids having a pleasant fruity smell. Reactivity depends on breaking the ester linkage.
Amides
May be unsubstituted or mono- or di-substituted.
The vast majority of amides are colourless solids. Characterisation involves hydrolysis.
Cyanides (or Nitriles)
Compounds possessing a triple bond between carbon and nitrogen atoms.
Most aliphatic and many aromatic cyanides are colourless liquids. Their most important reaction involves hydrolysis.
Amines
May be unsubstituted (prim) or mono- (sec) or di- (tert) substituted.
Many amines are liquids. Those that dissolve in water give a weakly basic solution. An aromatic amine has the amino group directly attached to the aromatic ring.
Amino Acids
Carboxylic acids with one or more amino groups.
Amino acids are often water soluble solids which decompose rather than melt on heating.
Nitro Compounds
Usually aromatic but some aliphatic examples exist.
Most aromatic nitro compounds vary in colour from pale to deep yellow or red. This colour often intensifies on treatment with base.
Thiols
Also known as mercaptans and the aromatic ones as thiophenols.
These compounds are usually liquids. They have most unpleasant characteristic odours.
Sulfonic acids
Most commonly aromatic in nature.
Sulfonic acids are solids which are readily soluble in water.