Question

Classify the following substances as a Bronsted-Lowry acid, Bronsted-Lowry base, Lewis acid, and/or Lewis base.HCl, BF_3,CCl_3, -HCH_2O, CH_3Cl-OCH_3 , NH_3

Answer 1

Answer:

HCl is a Bronsted acid, dissociates partially or completely with the release of H+ dissociating as H+ and Cl-.

BF_3 is a Lewis acid because it has an incomplete octet and an empty 2p orbital, so it can accept a lone pair. It is clearly not a Bronsted acid as it does not have a H+ to release on dissociation.

CCl_3  Lewis base

-H Lewis base

CH_2O  Bronsted base

CH_3Cl  Bronsted acid

-OCH_3 Lewis base

NH_3 is a Lewis Base:, N has a a lone pair which it can donate to a Lewis acid like BF3.  

Explanation:

The Brønsted-Lowry theory describes acid-base interactions in terms of proton transfer between chemical species. A Brønsted-Lowry acid is any species that can donate a proton, H+, and a base is any species that can accept a proton. As for chemical structure, this means that any Brønsted-Lowry acid must contain a hydrogen that can be dissociated as H+. To accept a proton, a Brønsted-Lowry base must have at least one solitary pair of electrons to form a new bond with a proton.