Alkyl group with more than four carbons

The four-carbon dividing line is only an approximate guide because the solubility of an alcohol also depends on the stmcture of the alkyl group. Alcohols with branched alkyl groups are more soluble in water than alcohols with nonbranched alkyl groups with the same number of carbons, because branching minimizes the contact surface of the nonpolar portion of the molecule. So ferf-butyl alcohol is more soluble than n-butyl alcohol in water. 

Naming three- and four-carbon alkyl groups is more complicated because the parent hydrocarbons have more than one type of hydrogen atom. For example, propane has both 1 and 2° H atoms, and removal of each of these H atoms forms a different alkyl group with a different name, propyl or isopropyl. 

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