Which is the stronger base: 2-Chloroethylamine or methylamine?

Amines are basic. This is because the lone pair of electrons on the nitrogen atom in each amine molecule is available to accept a proton (H⁺ ion).

Cl atom is electron withdrawing. Therefore, methylamine is a stronger base than 2-chloroethylamine. This is because Cl atom is electron-withdrawing while alkyl groups are electron-releasing (electron-donating) and thus :

(1) The indirect inductive effect of the electron-withdrawing chlorine atom can lower the electron density of the lone pair electrons on 2-chloroethylamine. Therefore, the lone pair of electron on the nitrogen atom of 2-chloroethylamine is less available to accept a proton, and thus the basic strength of 2-chloroethylamine is weaker than methylamine.

(2) The indirect inductive effect of the electron-withdrawing chlorine atom can also make the ammonium cation less stable. Therefore, 2-chloroethylamine has a lower tendency to accept a proton than methylamine.