5. Which Of The Following Pairs Constitutes A Buffer?(a) NaOH And HCl (b) $HNO_3$ And $NH_4NO_3$ (c) HCl And KCl (d) $HNO_2$ And $NaNO_2$

Introduction

In chemistry, a buffer solution is a mixture of a weak acid and its conjugate base, or a weak base and its conjugate acid. Buffer solutions are used to maintain a stable pH in various chemical reactions and applications. In this article, we will discuss the concept of buffer solutions and identify which of the given pairs constitutes a buffer.

What is a Buffer Solution?

A buffer solution is a mixture of a weak acid and its conjugate base, or a weak base and its conjugate acid. The weak acid or base does not completely dissociate in water, resulting in a solution with a relatively stable pH. Buffer solutions are used to prevent large changes in pH when small amounts of acid or base are added to the solution.

Types of Buffer Solutions

There are two main types of buffer solutions:

• Acidic Buffer Solution: A mixture of a weak acid and its conjugate base.
• Basic Buffer Solution: A mixture of a weak base and its conjugate acid.

Examples of Buffer Solutions

Some common examples of buffer solutions include:

• Acetic Acid and Sodium Acetate: A mixture of acetic acid (CH3COOH) and sodium acetate (CH3COONa).
• Ammonium Chloride and Ammonia: A mixture of ammonium chloride (NH4Cl) and ammonia (NH3).
• Phosphoric Acid and Sodium Phosphate: A mixture of phosphoric acid (H3PO4) and sodium phosphate (Na3PO4).

Which of the Following Pairs Constitutes a Buffer?

Now, let's examine the given pairs and determine which one constitutes a buffer.

(a) NaOH and HCl

NaOH (sodium hydroxide) is a strong base, and HCl (hydrochloric acid) is a strong acid. When mixed together, they completely dissociate in water, resulting in a solution with a pH that is not stable. Therefore, this pair does not constitute a buffer.

(b) $HNO_3$ and $NH_4NO_3$

$HNO_3$ (nitric acid) is a strong acid, and $NH_4NO_3$ (ammonium nitrate) is a salt of a weak acid and a strong base. When mixed together, they do not form a buffer solution because $HNO_3$ is a strong acid and completely dissociates in water.

(c) HCl and KCl

HCl (hydrochloric acid) is a strong acid, and KCl (potassium chloride) is a salt of a strong acid and a strong base. When mixed together, they do not form a buffer solution because HCl is a strong acid and completely dissociates in water.

(d) $HNO_2$ and $NaNO_2$

$HNO_2$ (nitrous acid) is a weak acid, and $NaNO_2$ (sodium nitrite) is a salt of a weak acid and a strong base. When mixed together, they form a buffer solution because $HNO_2$ is a weak acid and does not completely dissociate in water.

Conclusion

In conclusion, the pair that constitutes a buffer is (d) $HNO_2$ and $NaNO_2$. This pair forms a buffer solution because $HNO_2$ is a weak acid and does not completely dissociate in water. Buffer solutions are used to maintain a stable pH in various chemical reactions and applications, and understanding which pairs constitute a buffer is essential in chemistry.

References

• Atkins, P. W., & De Paula, J. (2010). Physical Chemistry (9th ed.). Oxford University Press.
• Brown, T. E., & LeMay, H. E. (2014). Chemistry: The Central Science (13th ed.). Pearson Education.
• Petrucci, R. H., Harwood, W. S., & Herring, F. G. (2016). General Chemistry: Principles and Modern Applications (11th ed.). Pearson Education.
  Buffer Solutions: A Comprehensive Q&A Guide =====================================================

Introduction

Buffer solutions are a crucial concept in chemistry, and understanding them is essential for various applications in fields such as biology, medicine, and environmental science. In this article, we will provide a comprehensive Q&A guide to buffer solutions, covering their definition, types, examples, and more.

Q: What is a Buffer Solution?

A: A buffer solution is a mixture of a weak acid and its conjugate base, or a weak base and its conjugate acid. The weak acid or base does not completely dissociate in water, resulting in a solution with a relatively stable pH.

Q: What are the Types of Buffer Solutions?

A: There are two main types of buffer solutions:

• Acidic Buffer Solution: A mixture of a weak acid and its conjugate base.
• Basic Buffer Solution: A mixture of a weak base and its conjugate acid.

Q: What are some Examples of Buffer Solutions?

A: Some common examples of buffer solutions include:

• Acetic Acid and Sodium Acetate: A mixture of acetic acid (CH3COOH) and sodium acetate (CH3COONa).
• Ammonium Chloride and Ammonia: A mixture of ammonium chloride (NH4Cl) and ammonia (NH3).
• Phosphoric Acid and Sodium Phosphate: A mixture of phosphoric acid (H3PO4) and sodium phosphate (Na3PO4).

Q: Which of the Following Pairs Constitutes a Buffer?

A: The pair that constitutes a buffer is (d) $HNO_2$ and $NaNO_2$. This pair forms a buffer solution because $HNO_2$ is a weak acid and does not completely dissociate in water.

Q: What is the Purpose of Buffer Solutions?

A: Buffer solutions are used to maintain a stable pH in various chemical reactions and applications. They are essential in fields such as biology, medicine, and environmental science.

Q: How are Buffer Solutions Prepared?

A: Buffer solutions can be prepared by mixing a weak acid and its conjugate base, or a weak base and its conjugate acid. The ratio of the weak acid or base to its conjugate base or acid can be adjusted to achieve the desired pH.

Q: What are the Advantages of Buffer Solutions?

A: The advantages of buffer solutions include:

• Maintaining a Stable pH: Buffer solutions can maintain a stable pH in various chemical reactions and applications.
• Preventing Large Changes in pH: Buffer solutions can prevent large changes in pH when small amounts of acid or base are added to the solution.
• Stabilizing Chemical Reactions: Buffer solutions can stabilize chemical reactions by maintaining a stable pH.

Q: What are the Disadvantages of Buffer Solutions?

A: The disadvantages of buffer solutions include:

• Limited pH Range: Buffer solutions can only maintain a stable pH within a limited range.
• Dependence on Concentration: Buffer solutions can be dependent on the concentration of the weak acid or base.
• Potential for Instability: Buffer solutions can be unstable if the ratio of the weak acid or base to its conjugate base or acid is not adjusted correctly.

Conclusion

In conclusion, buffer solutions are a crucial concept in chemistry, and understanding them is essential for various applications in fields such as biology, medicine, and environmental science. This Q&A guide has provided a comprehensive overview of buffer solutions, covering their definition, types, examples, and more.

References

• Atkins, P. W., & De Paula, J. (2010). Physical Chemistry (9th ed.). Oxford University Press.
• Brown, T. E., & LeMay, H. E. (2014). Chemistry: The Central Science (13th ed.). Pearson Education.
• Petrucci, R. H., Harwood, W. S., & Herring, F. G. (2016). General Chemistry: Principles and Modern Applications (11th ed.). Pearson Education.