I know that sodium hydroxide dissociates into sodium cation and hydroxide, so it must be an Arrhenius base. I am also aware of the rule that all Arrhenius acids and bases are considered to be Brønsted-Lowry acids and bases. However, when it comes to sodium hydroxide itself, it seems as if it does not accept proton, but hydroxide does. And someone on this StackExchange stated that it is not a Brønsted-Lowry base, but an Arrhenius base. I am confused now. Is this an exception?
All Arrhenius acids and bases are also Bronsted-Lowry bases. According to this website,
The Bronsted-Lowry theory doesn't go against the Arrhenius theory in any way - it just adds to it.
Remember, when we write NaOH (aq), what we really mean is Na+ (aq) and OH- (aq). Sodium hydroxide is a Bronsted-Lowry base because the hydroxide ions that are a part of sodium hydroxide accept protons.