Question

Predict the products for the following Brondtrd-Lowry acid reaction with a base and identity the following. a. acid b. base c. Lewis acid d. Lewis base 1. AlCl3 +NH3 2. GaF3 +H2O

Answer 1

Short answers (products are Lewis adducts; no proton transfer unless hydrolysis occurs):

1) AlCl3 + NH3
- Product: Cl3Al←NH3 (often written AlCl3·NH3) — a coordinate (Lewis) adduct.
- a. Brønsted–Lowry acid: none (AlCl3 does not donate H+ here).
- b. Brønsted–Lowry base: NH3 (it is a Brønsted base in general, but no proton transfer occurs in this reaction).
- c. Lewis acid: AlCl3 (electron-pair acceptor).
- d. Lewis base: NH3 (electron-pair donor).

2) GaF3 + H2O
- Product (primary): F3Ga←H2O (or GaF3·H2O) — a coordination (Lewis) adduct of water to GaF3.
- a. Brønsted–Lowry acid: none for the simple adduct formation.
- b. Brønsted–Lowry base: H2O (can act as a Brønsted base in other contexts).
- c. Lewis acid: GaF3 (electron-pair acceptor).
- d. Lewis base: H2O (electron-pair donor).

Note: In excess water GaF3 can hydrolyze (a Brønsted–Lowry process): GaF3 + 3 H2O → Ga(OH)3 + 3 HF (here H2O donates protons to F–, producing HF), so then you do have Brønsted acid–base chemistry.