1. The problem statement, all variables and given/known data In the reaction with NH3, is specy BH3 a Lewis base ? 2. Relevant equations Lewis acid = electron acceptor Lewis base = electron donor 3. The attempt at a solution H electronegativity = 2.1 B electronegativity = 2.0 N electronegativity = 3 Since N-H bond is more electronegative than B-H bond, NH3 is more electronegative than BH3 which means that NH3 is more easily to accept electron. So, NH3 is Lewis acid, BH3 is Lewis base Is it correct?? My book says that NH3 is the base with no reason, and I doubt that.