Question

what is the theory of arrhenius and bronsted Lowry ?????

Answer 1

➡Arrhenius Acid

An Arrhenius acid is a molecule that when dissolved in water will donate an H+ in solution. Simply put, a proton donor.

The trick to recognizing an Arrhenius acid is to look for a molecule that starts with an H, and typically contains an oxygen or halogen.

Common examples of Arrhenius acids include:

Hydrochloric Acid – HCl

Nitric Acid – HNO3

Sulfuric Acid – H2SO4

Acetic Acid – HCH3CO2

and so many more…

An acid dissociating in water does not form a free-floating proton. Instead one of the water molecules in solution will grab the H+ yielding a hydronium or H3O+ ion. Here’s what happens when nitric acid dissociates in water.

➡Arrhenius Base

An Arrhenius base is a molecule that when dissolved in water will break down to yield an OH- or hydroxide in solution. To recognize the Arrhenius base look for a molecule ending in OH, but not following CHx which refers to an alcohol.

Arrhenius base examples include:

Sodium hydroxide – NaOH

Potassium hydroxide – KOH

Magnesium hydroxide – Mg(OH)2

and so many more…

➡Bronsted-Lowry Acid

A Bronsted-Lowry acid, like an Arrhenius acid, is a compound that breaks down to give an H+ in solution. The only difference is that the solution does not have to be water. We can still refer to the exact same acids as listed for the Arrhenius acid examples, but this time we’ll change the solvent to ammonia, alcohol, or anything else.

We saw what happens when nitric acid (HNO3) dissolves in water. Now let’s see what happens when it dissolves in ammonia (NH3) or even methanol (CH3OH)
Nitric acid still dissolved to yield an H+ and NO3-, but this time it was NH3 and not water that picked up the free-floating proton.

➡Bronsted-Lowry Base

This is where we start to see the difference between the Bronsted-Lowry and Arrhenius definitions. While the Arrhenius base referred specifically to the hydroxide (OH-) ion, the Bronsted-Lowry base refers to any atom or ion capable of accepting or bonding to a free proton in solution.

Referring back to the HNO3 + NH3 reaction above, when ammonia picks up the free H+ it acts as a proton-acceptor. NH3 is the Bronsted-Lowry base in this example.

Additional examples include:

Methanol – CH3OH

Formaldehyde – H2CO

And even water – H2O



Hope it helps you