Answer. Arrhenius concept of acids and bases was having limitations of applicable only in aqueous medium. But Bronsted Lowry concept has broader scope. It is applicable to non-aqueous solutions. According to this concept:
An acid is a substance (molecule or ion) that can donate a proton (H+) to another substance.
A base is a substance that can accept a proton (H+) from another substance.
This concept does not require an aqueous medium for an acid or a base to ionize. This concept requires only two substances; one act as an acid and the other acts as a base. It means an acid and a base always work together to transfer a proton. For example, a reaction between HC1 and NH3 takes place as follows
HCl(aq) + NH3(aq) NH4+(aq) + Cl-(aq)