Halogenoalkanes
These are created through radical substitution (see the post on that for more). The general formula for halogenoalkanes with one halogen is : "C(n)H(2n+1)X" where X shows a halogen such as Br or Cl There are Primary, Secondary and Tertiary halogenoalkanes, depending on the number of R groups or hydrogen atoms the adjoining carbon is attached to (like alcohols) The C-X bond has a dipole. The X is d- and the carbon is d+. This leaves it open to "attack" by negative nucleophiles, such as aqueous OH- ions. X- is a stable ion on its own, so X is substituted easily. This is known as nucleophilic subtitution. Because the C-F bond is the strongest (highest bond enthalpy), and the C-I bond is the weakest, fluoroalkanes are the least reactive and iodoalkanes are the most reactive.
image from http://www.chemhume.co.uk
Halogenoalkanes also react with water, in a hydrolysis reaction, to make alcohol. C2H5Br + H20 ---> C2H5OH + HBr.
