Which theory is correct Arrhenius or Bronsted Lowry theory?
The Bronsted-Lowry theory doesn't go against the Arrhenius theory in any way - it just adds to it.
Hydroxide ions are still bases because they accept hydrogen ions from acids and form water.
An acid produces hydrogen ions in solution because it reacts with the water molecules by giving a proton to them.
1. According to the Arrhenius, acids give up hydrogen ion in aqueous medium and a base give up hydroxyl ion in its aqueous medium. Examples are aqueous solution of HCl, CH3COOH, PhCOOH, and H2SO4. These give up H+ in an aqueous medium. Aqueous solutions of NaOH, Ca (OH)2 are Arrhenius bases.
Arrhenius theory has some limitations. This theory cannot explain the acidic nature of BF3 or basic behavior of NH3. This theory fails to give any explanation about acidity and basicity which does not produce H+ and OH- in their aqueous solutions.
2. According to the Bronsted-Lowry, an acid releases proton and a base accepts proton. NH3 accepts proton and forms ammonium ion, so ammonia acts as a base.
But this theory also has limitations. According to this theory acidic behavior of BF3 still cannot be explained.