Is ethylamine a Bronsted-Lowry base?

Yes, ethylamine, ##CH_3CH_2NH_2##, can act as a because of the lone pair of electrons present on the nitrogen atom.

For example, when it reacts with water, ethylamine will accept a proton, ##H^(+)##, from water and form the ethylammonium ion.

##CH_3CH_2NH_(2(aq)) + H_2O_((l)) rightleftharpoons overbrace(CH_3CH_2NH_(3(aq))^(+))^(color(blue)("ethylammonium ion")) + OH_((aq))^(-)##

By definition, any compound that can act as a proton acceptor is a .