What type of reaction do haloalkanes undergo with nucleophiles?

Halogens are electronegative than the adjacent carbon atoms in haloalkanes.Therefore they have a tendency to attract the pair of electrons in a covalent bond, forming a polar bond.The carbon becomes electron deficient and therefore attracts the nucleophile (electron donor).The reaction will be a nucleophilic substitution where the nucleophile replaces the halide - in this case forming an alcohol.
CH3CH2CL + OH- —> CH3CH2OH + Cl-