The bronsted-lowry theory
The bronsted-lowry theory is an addition to the Arrhenius theory which defines acids and bases there are many reactions that occur in solvents or without any solvents at all rather than water. The reaction between hydrogen chloride and ammonia can be used to explain it. In aqueous solution, hydrogen which is an acid reacts with ammonia, a base to form a solution of the salt: ammonium chloride. According to Arrhenius the reaction occurs between the H+ ions formed due to the ionisation of the HCl when it dissolved in water. The OH- ion is also formed when ammonia dissolves in water.
NH3 + H2O NH4 + OH- HCl + H2O Cl- + H2O-
However, the reaction between ammonia and hydrogen chloride doesn’t need water or any other solvent to take place. When the gases of ammonia and hydrogen chloride react, white fume containing crystals of ammonium chloride is formed as a product of the reaction between the two. This is same reaction that occurs in water they are both acid-base reactions. But according to Arrhenius this reaction cannot take place because there is no reaction between the H3O+ and OH-.
A Danish chemist named Johannes Nicolaus bronstead recognised the problem together with an English chemist named Thomas Martin Lowry , they formed a more general definition of acids which states the following :
An acid is a proton donor
An base is a proton acceptor Using this definition we can define the reaction between the hydrogen chlorine and ammonia as an acid-base reaction. This is because the HCL molecule is seen as the proton donor and the ammonia molecule is seen as the proton acceptor. Below is the reaction: NH3(g) + HCl(g) ----- > NH4+Cl-(s)
Due to the Bronstead-Lowry theory definition ,when an acid disassociate , we can regard it to be an acid base reaction that is in equilibrium. In this above equation we have HA ,which is an acid because it donates a proton and Water which is a base because it
NH3 + H2O NH4 + OH- HCl + H2O Cl- + H2O-
However, the reaction between ammonia and hydrogen chloride doesn’t need water or any other solvent to take place. When the gases of ammonia and hydrogen chloride react, white fume containing crystals of ammonium chloride is formed as a product of the reaction between the two. This is same reaction that occurs in water they are both acid-base reactions. But according to Arrhenius this reaction cannot take place because there is no reaction between the H3O+ and OH-.
A Danish chemist named Johannes Nicolaus bronstead recognised the problem together with an English chemist named Thomas Martin Lowry , they formed a more general definition of acids which states the following :
An acid is a proton donor
An base is a proton acceptor Using this definition we can define the reaction between the hydrogen chlorine and ammonia as an acid-base reaction. This is because the HCL molecule is seen as the proton donor and the ammonia molecule is seen as the proton acceptor. Below is the reaction: NH3(g) + HCl(g) ----- > NH4+Cl-(s)
Due to the Bronstead-Lowry theory definition ,when an acid disassociate , we can regard it to be an acid base reaction that is in equilibrium. In this above equation we have HA ,which is an acid because it donates a proton and Water which is a base because it