Question

An Acid-Base Titration Lab

Define Lewis acids and bases. Give an example of each.

Based on the Brønsted-Lowry theory of acids and bases, complete the equations for the following acid-base reactions. In your answer be sure to indicate each conjugate acid-base pair:

HNO₃ + OH^- à

CH₃NH₂ + H₂O à

OH^- + HPO₄^-2 à

When discussing the theories of acids and bases, the Arrhenius, Brønsted-Lowry, and Lewis theories will each describe compounds in their own unique and different way. Based on each of the three theories, describe KOH.

4.Water is a substance that can act as both an acid and a base. Explain this based on the three ways that you can use to define acids and bases.

Answer 1

1.Lewis acid: Any substance that accepts a pair of electrons is called Lewis acid

Ex: All cations, AlCl3 etc.,

Lewis Base: Any substance that donates a pair of electrons is called Lewis base

Ex: All anions, NH3 etc.,

2. A pair of substances that differentiated by a proton is said be its conjugate acid/base

HNO₃(acid) + OH^-(base) ----> H₂O(conjugate acid of OH-) + NO₃^- (conjugate base of HNO3)

CH₃NH₂(base) + H₂O(acid) ----> CH₃NH₃⁺(conjugate acid of CH3NH2) + OH^-(conjugate base of H2O)

OH^- (base)+ HPO₄^-2(acid) ----> H₂O (conjugate acid of OH-)+ PO₄^3-(conjugate base of HPO4^2-)

3. According to Arhenius theory, KOH is a base because it produces OH- ions in water

According Bronsted-Lowry theory, it is a base because it accepts H+ with acids

KOH + HCl ----> KCl + H2O

According to Lewis theory, KOH is a base because it donates a pair of electrons to bind with proton