Select The Correct Answer.Which Statement Correctly Relates Two Substances From This Reaction? $H_2CO_3 + H_2O \rightleftharpoons H_3O^{+} + HCO_3^{-}$A. $HCO_3^{-}$ Is The Conjugate Acid Of $H_2CO_3$. B. $H_2O$ Is

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Introduction

Acid-base equilibria are a fundamental concept in chemistry, and understanding the relationships between different substances in these reactions is crucial for grasping the underlying principles. In this article, we will delve into the carbonic acid reaction, examining the relationships between the substances involved and identifying the correct statement that relates two substances from this reaction.

The Carbonic Acid Reaction

The carbonic acid reaction is a well-known acid-base equilibrium that involves the dissociation of carbonic acid (H2CO3) in water (H2O). The reaction is as follows:

H2CO3+H2O⇌H3O++HCO3−H_2CO_3 + H_2O \rightleftharpoons H_3O^{+} + HCO_3^{-}

In this reaction, carbonic acid (H2CO3) reacts with water (H2O) to form hydronium ions (H3O+) and bicarbonate ions (HCO3-). This reaction is an example of a weak acid dissociating in water, resulting in the formation of a conjugate base (HCO3-) and a conjugate acid (H3O+).

Analyzing the Statements

Now that we have a clear understanding of the carbonic acid reaction, let's analyze the two statements provided:

A. HCO3−HCO_3^{-} is the conjugate acid of H2CO3H_2CO_3.

B. H2OH_2O is the conjugate base of H3O+H_3O^{+}.

Statement A: HCO3−HCO_3^{-} is the conjugate acid of H2CO3H_2CO_3

To determine if statement A is correct, we need to understand the concept of conjugate acids and bases. A conjugate acid is a species that is formed when a base accepts a proton (H+). In the context of the carbonic acid reaction, carbonic acid (H2CO3) is the acid that donates a proton to form bicarbonate ions (HCO3-). Therefore, bicarbonate ions (HCO3-) are the conjugate base of carbonic acid (H2CO3), not the conjugate acid.

Statement B: H2OH_2O is the conjugate base of H3O+H_3O^{+}

To determine if statement B is correct, we need to understand the concept of conjugate acids and bases. A conjugate base is a species that is formed when an acid donates a proton (H+). In the context of the carbonic acid reaction, water (H2O) is the solvent that accepts a proton from carbonic acid (H2CO3) to form hydronium ions (H3O+). Therefore, water (H2O) is the conjugate base of hydronium ions (H3O+), not the conjugate acid.

Conclusion

In conclusion, statement A is incorrect because bicarbonate ions (HCO3-) are the conjugate base of carbonic acid (H2CO3), not the conjugate acid. Statement B is also incorrect because water (H2O) is the conjugate base of hydronium ions (H3O+), not the conjugate acid.

Key Takeaways

  • The carbonic acid reaction is a well-known acid-base equilibrium that involves the dissociation of carbonic acid (H2CO3) in water (H2O).
  • Bicarbonate ions (HCO3-) are the conjugate base of carbonic acid (H2CO3), not the conjugate acid.
  • Water (H2O) is the conjugate base of hydronium ions (H3O+), not the conjugate acid.

References

  • Atkins, P. W., & De Paula, J. (2010). Physical chemistry (9th ed.). Oxford University Press.
  • Brown, T. E., LeMay, H. E., Bursten, B. E., Murphy, C. M., & Woodward, P. (2012). Chemistry: The Central Science (12th ed.). Pearson Education.

Further Reading

  • Acid-base equilibria
  • Conjugate acids and bases
  • Carbonic acid reaction

Related Topics

  • Acid-base chemistry
  • Equilibrium reactions
  • Conjugate acid-base pairs
    Frequently Asked Questions: Understanding Acid-Base Equilibria ====================================================================

Q: What is acid-base equilibria?

A: Acid-base equilibria refers to the dynamic balance between acids and bases in a solution. It involves the exchange of protons (H+) between acids and bases, resulting in the formation of conjugate acids and bases.

Q: What is a conjugate acid?

A: A conjugate acid is a species that is formed when a base accepts a proton (H+). In other words, it is the acid that is formed when a base donates a proton.

Q: What is a conjugate base?

A: A conjugate base is a species that is formed when an acid donates a proton (H+). In other words, it is the base that is formed when an acid donates a proton.

Q: What is the difference between a strong acid and a weak acid?

A: A strong acid is an acid that completely dissociates in water, resulting in the formation of a high concentration of hydronium ions (H3O+). A weak acid, on the other hand, only partially dissociates in water, resulting in a lower concentration of hydronium ions.

Q: What is the difference between a strong base and a weak base?

A: A strong base is a base that completely dissociates in water, resulting in the formation of a high concentration of hydroxide ions (OH-). A weak base, on the other hand, only partially dissociates in water, resulting in a lower concentration of hydroxide ions.

Q: What is the pH scale?

A: The pH scale is a measure of the concentration of hydronium ions (H3O+) in a solution. It ranges from 0 to 14, with a pH of 7 being neutral (neither acidic nor basic).

Q: What is the pOH scale?

A: The pOH scale is a measure of the concentration of hydroxide ions (OH-) in a solution. It is related to the pH scale by the equation pOH = 14 - pH.

Q: What is the relationship between pH and pOH?

A: The pH and pOH scales are inversely related. As the pH increases, the pOH decreases, and vice versa.

Q: What is the Henderson-Hasselbalch equation?

A: The Henderson-Hasselbalch equation is a mathematical expression that relates the pH of a solution to the concentrations of the acid and its conjugate base. It is given by the equation pH = pKa + log10([A-]/[HA]).

Q: What is the significance of the pKa value?

A: The pKa value is a measure of the strength of an acid. It is the pH at which the acid is 50% dissociated. A low pKa value indicates a strong acid, while a high pKa value indicates a weak acid.

Q: What is the significance of the pKb value?

A: The pKb value is a measure of the strength of a base. It is the pOH at which the base is 50% dissociated. A low pKb value indicates a strong base, while a high pKb value indicates a weak base.

Conclusion

In conclusion, acid-base equilibria is a fundamental concept in chemistry that involves the exchange of protons between acids and bases. Understanding the relationships between acids and bases is crucial for grasping the underlying principles of acid-base chemistry. The pH and pOH scales are important tools for measuring the acidity and basicity of a solution, and the Henderson-Hasselbalch equation is a useful mathematical expression for relating the pH of a solution to the concentrations of the acid and its conjugate base.

Key Takeaways

  • Acid-base equilibria involves the exchange of protons between acids and bases.
  • Conjugate acids and bases are formed when acids and bases donate or accept protons.
  • The pH and pOH scales are important tools for measuring the acidity and basicity of a solution.
  • The Henderson-Hasselbalch equation is a useful mathematical expression for relating the pH of a solution to the concentrations of the acid and its conjugate base.

Further Reading

  • Acid-base chemistry
  • Equilibrium reactions
  • Conjugate acid-base pairs
  • pH and pOH scales
  • Henderson-Hasselbalch equation

Related Topics

  • Acid-base chemistry
  • Equilibrium reactions
  • Conjugate acid-base pairs
  • pH and pOH scales
  • Henderson-Hasselbalch equation