For the following three reactions, identify the reactants that are Arrhenius bases,
Brønsted-Lowry bases, and/or Lewis bases. State the type(s) of bases in each
case. Explain your answer.
a NaOH (s) Æ Na+ (aq) + OH– (aq)
b HF (aq) + H2O (l) Æ F–(aq) + H3O+ (aq)
c H+ (aq) + NH3 (aq) Æ NH+
4 (aq)�
a) NaOH is an Arrhenius base and a Brønsted-Lowry base because it dissociates in water to produce OH- ions, which can accept H+ ions to form water. It is not a Lewis base because it does not donate a lone pair of electrons.
b) HF is a Brønsted-Lowry acid because it donates a proton to the water molecule, forming H3O+. It is also a Lewis base because it donates its lone pair of electrons to the H+ ion in the product. F- is a Brønsted-Lowry base because it accepts a proton to form HF, and a Lewis base because it donates its lone pair of electrons to form a bond with the H+ ion.
c) NH3 is a Brønsted-Lowry base because it accepts a proton from H+ to form NH4+. It is also a Lewis base because it donates its lone pair of electrons to form a bond with the H+ ion. NH4+ is a Brønsted-Lowry acid because it can donate a proton, and it is not a Lewis base because it does not donate a lone pair of electrons.