Bronsted-Lowry Concept of Acids and Bases

 The Danish chemist J. N. Bronsted and an English chemist T. M. Lowry independently expanded the Arrhenius acid and base definitions. According to this concept,

A Bronsted-Lowry acid is a substance (molecule or ion) that is a proton (H+) donor, whereas a Bronsted-Lowry base is a substance (molecule or ion) that is a proton (H+) acceptor. 

For Example              





Hydrochloric acid acts as a Bronsted-Lowry acid when it reacts with ammonia. In this example, (HCl) donates a proton and acts as an acid, while ammonia (NH3) accepts a proton to form an ammonium ion (NH4+) and serves as a base.

 Water can also act as a Bronsted-Lowry acid.  For example,  The following reaction, in which the H2O molecule gives a proton to the NH3. 



In another example, water acts as a Bronsted-Lowry base as it accepts a proton from HCI, which act as an acid. 

Therefore, the water (H20) molecule acts both as an acid well as a base (amphoteric).

Some Arrhenius hydroxide bases, such as NaOH, are not Bronsted-Lowry bases. It is because these compounds are not proton acceptors whereas, the OH- ion produced in a solution is the Bronsted-Lowry base because it is the species that can accept a proton




Comments

Post a Comment

Popular posts from this blog

Simple Definition of Arrhenius Acid and Base

  Simple Definition of Arrhenius Acid and Base Arrhenius Acids An acid is a chemical substance that dissociates in an aqueous solution to give hydrogen ions (H+) A substance such as HCl, H2SO4, HNO3, CH3COOH, HCN, etc, is acids because they ionize in an aqueous solution to produce H+ ions. Arrhenius Base Arrhenius base is a chemical substance that dissociates in an aqueous solution to give hydroxide ions (OH -) The substances such as NaOH, KOH, NH4OH, Mg(OH)2, etc are bases because they ionize in aqueous solutions to provide OH- ions
Read more

At Dynamic Equilibrium?

 At Dynamic Equilibrium a)  The reverse reaction stops b)  The forward reaction stops c)  Both forward and reverse reactions stop d) Both Forward and reverse reactions continue at the same rate Correct Answer (d) Because in dynamic equilibrium A reaction that does not stop at equilibrium, the rate of forwarding and reverse reaction remains equal
Read more

Limitations of Arrhenius Concept

 The limitations of Arrhenius concept are Arrhenius concept is only limited to aqueous medium and dose not explain the acidity and basicity of the substance in non equeous medium  In Arrhenius concept acids are limited to hydrogen ion (H+) only and bases are limited to hydroxide ion (OH-). It cannot explain the acidic nature of carbon dioxide (CO2) and basic nature of ammonia (NH3) 
Read more

Chemistry class 10th Acid Base and Salt MCQs in pakistan Text Book

 Chemistry class 10th Acid Base and Salt MCQs in pakistan Text Book According to the Arrhenius concept, which of the following is not and acid a)  HCl b)  H2SO4 c)  CO2 d)  HNO3 C is the Correct answer AlCl3 is an acid according to  a)  Arrhenius b)  Lowery and Bronsted c)  Lewis  d)  All of these C is the Correct answer Which of the following is a Lweis base? a)  HCl b)  AlCl3 c)  BF3 d)  F negative D is the Correct Answer Neutral solution has a PH value of  a)  3 b)  5 c)  7 d)  14 C is the Correct Answer The POH of 0.001M solution of nitric acid is a)  0.001 b)  10.0 c)  11 d)  14 C is the Correct Answer When strong base and weak acid reacts, the only products are a)  Neutral salt and water b)  Basic salt and water c)  Acidic salt and water d)  Acidic, basic salt and water b is the Correct Answer NH3 is base according to  a)  Arrhenius...
Read more