Question

hat is the pH of a 04 a) Wri will ee which nf ononm dissori.. General Chemistry II Workshop 3: Acid-Base Equilibria (10 pts total) In today's workshop we will explore two classes of compounds known as acids and bases. Acids were first identified as compounds that taste sour while bases were first identified as compounds that feel slippery and taste bitter. Today there are 3 prevailing theories that define acids and bases. We will spend most of our time in GenChem using the Brønsted-Lowry Theory Definition of Base The Arrhenius Brensten-Lowry Proton (H) donor Lewis Definition of Acid Produce H ions in aqueous solution Produce OH ion in aqueous solution Electron pair acceptor Proton (H') acceptor Electron pair donor Strong acids dissociate completely in aqueous solution. This means that in solution every molecule of strong acid will lose its acidic protorn. Weak acids do not completely dissociate in aqueous solution. That means that at any given moment most of the weak acid molecules will be found in solution as molecules and only a few molecules will dissociate and donate protons. Dissociation of a weak acid in aqueous solution is an equilibrium process. Every weak acid has a measured acid dissociation constant, K, ("a" stands for acid). Like all equilibrium constants K, tells you how far in the forwards direction the reaction (dissociation) proceeds until it reaches equilibrium. The lower the Ka value the fewer weak acid molecules will dissociate. 1. Consider a 1.00M solutien of weak nitrous acid. a) Write the equilibrium reaction for the aqueous dissociation of this acid. + H20 b) In the space above, label the acid, base, conjugate acid and conjugate base. c) Now let's draw a picture that models the microscopic behavior of this acid. Draw in the box below what you expect to see on a molecular level when you study a sample of an aqueous solution of HNO2. Don't forget to label species. Before you draw the picture discuss with your group the following questions: Do you expect all of the acid molecules to dissociate? If not, what do you expect to see? How do you want to model/depict molecules? ions? Do you think you need to include any water molecules in your diagram?

Answer 1

(a) HNO₂ + H₂O = NO₂^- + H₃O⁺

Here, in this reaction HNO2 gives one H⁺ ion, so it behaves as acid and H₂O accepts H⁺ so it behaves as base ( By Bronsten- Lowry concept).

(b) HNO₂ acts as acid and NO₂^- will be conjugate base.

And H₂O acts as base and H₃O⁺ will be conjugate acid.