Ch.15 - Acid and Base EquilibriumWorksheetSee all chapters
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Ch.1 - Intro to General Chemistry
Ch.2 - Atoms & Elements
Ch.3 - Chemical Reactions
BONUS: Lab Techniques and Procedures
BONUS: Mathematical Operations and Functions
Ch.4 - Chemical Quantities & Aqueous Reactions
Ch.5 - Gases
Ch.6 - Thermochemistry
Ch.7 - Quantum Mechanics
Ch.8 - Periodic Properties of the Elements
Ch.9 - Bonding & Molecular Structure
Ch.10 - Molecular Shapes & Valence Bond Theory
Ch.11 - Liquids, Solids & Intermolecular Forces
Ch.12 - Solutions
Ch.13 - Chemical Kinetics
Ch.14 - Chemical Equilibrium
Ch.15 - Acid and Base Equilibrium
Ch.16 - Aqueous Equilibrium
Ch. 17 - Chemical Thermodynamics
Ch.18 - Electrochemistry
Ch.19 - Nuclear Chemistry
Ch.20 - Organic Chemistry
Ch.22 - Chemistry of the Nonmetals
Ch.23 - Transition Metals and Coordination Compounds

Solution: What will the predominant species in H 2CO3 at pH of 7.5?


What will the predominant species in H 2CO3 at pH of 7.5?


We are asked to identify the predominant species in H2CO3 at pH=7.5

Recall that H2CO3 is a diprotic acidan acid which can donate up to two protons [H+] in solution. It has two Ka values for each proton dissociation as follows:

H2CO3(aq)+  H2O(aq)  ⇌  HCO3-(aq)  + H3O+(aq)       Ka1 = 4.5 x 10-7

HCO3-(aq)+  H2O(aq)  ⇌  CO32-(aq)  + H3O+(aq)          Ka2 = 4.7 x 10-11

Note: You can check on Ka values in books or the internet. 

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