Which Of The Following Is The Conjugate Acid Of $H _2 PO _4^{-}$?A. $H _4 PO _4^{-}$ B. $ P O 4 3 − PO _4{ }^{3-} P O 4 ​ 3 − [/tex] C. $H _3 PO _4$ D. $HPO _4^{-2}$

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Introduction

In chemistry, conjugate acids and bases play a crucial role in understanding acid-base reactions. A conjugate acid is a species that is formed when a base accepts a proton (H+ ion). In this article, we will explore the concept of conjugate acids and identify the conjugate acid of the given species, $H_2PO_4^{-}$.

What is a Conjugate Acid?

A conjugate acid is a species that is formed when a base accepts a proton (H+ ion). This process is known as protonation. The conjugate acid of a base has a higher charge than the original base. For example, the conjugate acid of water (H2O) is hydronium ion (H3O+).

Understanding the Species $H_2PO_4^{-}$

The species $H_2PO_4^{-}$ is a dihydrogen phosphate ion. It is a conjugate base of phosphoric acid (H3PO4). The dihydrogen phosphate ion has a charge of -1 and contains two hydrogen atoms bonded to the phosphate group.

Identifying the Conjugate Acid

To identify the conjugate acid of $H_2PO_4^{-}$, we need to consider the process of protonation. When $H_2PO_4^{-}$ accepts a proton (H+ ion), it forms a new species with a higher charge. The conjugate acid of $H_2PO_4^{-}$ is formed by adding a proton to the dihydrogen phosphate ion.

Analyzing the Options

Let's analyze the given options:

A. $H_4PO_4^{-}$ B. $PO_4^{3-}$ C. $H_3PO_4$ D. $HPO_4^{-2}$

Option A: $H_4PO_4^{-}$

The species $H_4PO_4^{-}$ is a tetrahydrogen phosphate ion. It has a charge of -1 and contains four hydrogen atoms bonded to the phosphate group. However, this species is not the conjugate acid of $H_2PO_4^{-}$, as it has the same charge and number of hydrogen atoms.

Option B: $PO_4^{3-}$

The species $PO_4^{3-}$ is a phosphate ion. It has a charge of -3 and contains no hydrogen atoms bonded to the phosphate group. This species is not the conjugate acid of $H_2PO_4^{-}$, as it has a different charge and no hydrogen atoms.

Option C: $H_3PO_4$

The species $H_3PO_4$ is phosphoric acid. It has a charge of 0 and contains three hydrogen atoms bonded to the phosphate group. This species is the conjugate acid of $H_2PO_4^{-}$, as it has a higher charge and more hydrogen atoms.

Option D: $HPO_4^{-2}$

The species $HPO_4^{-2}$ is a monohydrogen phosphate ion. It has a charge of -2 and contains one hydrogen atom bonded to the phosphate group. This species is not the conjugate acid of $H_2PO_4^{-}$, as it has a different charge and fewer hydrogen atoms.

Conclusion

In conclusion, the conjugate acid of $H_2PO_4^{-}$ is $H_3PO_4$. This species has a higher charge and more hydrogen atoms than the original species. Understanding conjugate acids and bases is crucial in chemistry, as it helps us understand acid-base reactions and the behavior of different species.

Key Takeaways

  • A conjugate acid is a species that is formed when a base accepts a proton (H+ ion).
  • The conjugate acid of a base has a higher charge than the original base.
  • The species $H_2PO_4^{-}$ is a dihydrogen phosphate ion.
  • The conjugate acid of $H_2PO_4^{-}$ is $H_3PO_4$.

References

  • Atkins, P. W., & De Paula, J. (2010). Physical chemistry. Oxford University Press.
  • Brown, T. E., & LeMay, H. E. (2014). Chemistry: The Central Science. Pearson Education.
  • Petrucci, R. H., Harwood, W. S., & Herring, F. G. (2016). General chemistry: Principles and modern applications. Pearson Education.
    Conjugate Acids and Bases: A Q&A Guide =============================================

Introduction

In our previous article, we explored the concept of conjugate acids and bases in chemistry. In this article, we will answer some frequently asked questions about conjugate acids and bases.

Q: What is the difference between a conjugate acid and a conjugate base?

A: A conjugate acid is a species that is formed when a base accepts a proton (H+ ion), while a conjugate base is a species that is formed when an acid donates a proton (H+ ion). In other words, a conjugate acid is the result of a base accepting a proton, while a conjugate base is the result of an acid donating a proton.

Q: How do conjugate acids and bases relate to acid-base reactions?

A: Conjugate acids and bases play a crucial role in acid-base reactions. When a base accepts a proton, it forms a conjugate acid, and when an acid donates a proton, it forms a conjugate base. This process is known as protonation and deprotonation, respectively.

Q: What is the relationship between pH and conjugate acids and bases?

A: The pH of a solution is related to the concentration of conjugate acids and bases. A solution with a high concentration of conjugate acids will have a low pH, while a solution with a high concentration of conjugate bases will have a high pH.

Q: Can a conjugate acid be a strong acid?

A: Yes, a conjugate acid can be a strong acid. For example, the conjugate acid of water (H2O) is hydronium ion (H3O+), which is a strong acid.

Q: Can a conjugate base be a strong base?

A: Yes, a conjugate base can be a strong base. For example, the conjugate base of hydrochloric acid (HCl) is chloride ion (Cl-), which is a strong base.

Q: How do conjugate acids and bases affect the pH of a solution?

A: Conjugate acids and bases can affect the pH of a solution by either increasing or decreasing the concentration of hydrogen ions (H+). A conjugate acid will increase the concentration of hydrogen ions, while a conjugate base will decrease the concentration of hydrogen ions.

Q: Can a conjugate acid be a weak acid?

A: Yes, a conjugate acid can be a weak acid. For example, the conjugate acid of acetic acid (CH3COOH) is acetate ion (CH3COO-), which is a weak acid.

Q: Can a conjugate base be a weak base?

A: Yes, a conjugate base can be a weak base. For example, the conjugate base of ammonia (NH3) is amide ion (NH2-), which is a weak base.

Q: How do conjugate acids and bases relate to buffer solutions?

A: Conjugate acids and bases play a crucial role in buffer solutions. A buffer solution is a solution that resists changes in pH when an acid or base is added. Conjugate acids and bases help to maintain the pH of a buffer solution by either increasing or decreasing the concentration of hydrogen ions.

Conclusion

In conclusion, conjugate acids and bases are an essential concept in chemistry. Understanding the relationship between conjugate acids and bases and acid-base reactions, pH, and buffer solutions is crucial in chemistry.

Key Takeaways

  • A conjugate acid is a species that is formed when a base accepts a proton (H+ ion).
  • A conjugate base is a species that is formed when an acid donates a proton (H+ ion).
  • Conjugate acids and bases play a crucial role in acid-base reactions.
  • The pH of a solution is related to the concentration of conjugate acids and bases.
  • Conjugate acids and bases can affect the pH of a solution by either increasing or decreasing the concentration of hydrogen ions.

References

  • Atkins, P. W., & De Paula, J. (2010). Physical chemistry. Oxford University Press.
  • Brown, T. E., & LeMay, H. E. (2014). Chemistry: The Central Science. Pearson Education.
  • Petrucci, R. H., Harwood, W. S., & Herring, F. G. (2016). General chemistry: Principles and modern applications. Pearson Education.