Question

Hi! So, I thought I was very comfortable with distinguishing among Arrhenius, Bronsted-Lowry, and Lewis acids and bases. But then, I answered this question wrong and am looking for help because I'm not sure if my "second choice" answer is correct.

The question asks: In the gas phase reacion below, NH3 is acting as a(n) _______ base but not as a(n) _______ base.

The reaction is illustrated in Lewis structures: NH3 (including the lone electron pair on the N) plus a single hydrogen, H+. Of course, the reaction produces NH4.

At this point, I want to say that NH3 is acting as an Arrhenius base but not a Lewis base. (My initial choice was the exact opposite - I guess not including water threw me off.)

ANY help or clarification would be greatly appreciated!

Answer 1

Arrhenius:
in water solution,
acid = provides H^+
base = provides OH^-

Bronsted-Lowry:
acid = proton donor
base = proton acceptor

Lewis:
acid = electron acceptor
base = electron donor

:NH3 + H^+ ==>NH4^+.

NH3 accepts a proton; therefore, it is acting as a Bronsted-Lowry base.
It is donating a pair of electrons, also, therefore, it is acting as a Lewis base.
No OH^- are involved; therefore, it is not acting as an Arrhenius base.

Answer 2

Thanks, Dr. Bob! It seems my initial thinking was correct. Perhaps the question was marked wrong by mistake!

Answer 3

kjbouho