Hexamethylenetetramine $\left(\left( CH _2\right)_6 N_4\right)$ Is A Weak Organic Base. A $7.0 \times 10^{-3} M$ Solution Of Hexamethylenetetramine Has A PH Of 8.37. The Amount Of $OH ^{-}$ That Dissociates Is

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Introduction

Hexamethylenetetramine, also known as methenamine, is a weak organic base with the chemical formula $\left(\left( CH _2\right)_6 N_4\right)$. It is a colorless crystalline solid that is highly soluble in water. In this article, we will explore the properties of hexamethylenetetramine and its behavior as a weak base.

Chemical Properties of Hexamethylenetetramine

Hexamethylenetetramine is a weak base, meaning that it does not completely dissociate in water. It has a pKa value of around 6.1, which indicates that it is a relatively weak base compared to other organic bases. The chemical structure of hexamethylenetetramine is a hexamethylene chain with four nitrogen atoms, which gives it its basic properties.

The pH of a Hexamethylenetetramine Solution

A $7.0 \times 10^{-3} M$ solution of hexamethylenetetramine has a pH of 8.37. This indicates that the solution is slightly alkaline, with a pH that is higher than neutral (pH 7). As a weak base, hexamethylenetetramine will partially dissociate in water to produce hydroxide ions ($OH ^{-}$).

Calculating the Amount of $OH ^{-}$ that Dissociates

To calculate the amount of $OH ^{-}$ that dissociates, we can use the Henderson-Hasselbalch equation:

pH=pKa+log⁡[A−][HA]pH = pK_a + \log \frac{[A^-]}{[HA]}

where $[A^-]$ is the concentration of the conjugate base (in this case, $OH ^{-}$) and $[HA]$ is the concentration of the weak acid (in this case, hexamethylenetetramine).

Rearranging the equation to solve for $[A^-]$, we get:

[A−]=[HA]×10(pH−pKa)[A^-] = [HA] \times 10^{(pH - pK_a)}

Plugging in the values, we get:

[A−]=7.0×10−3M×10(8.37−6.1)[A^-] = 7.0 \times 10^{-3} M \times 10^{(8.37 - 6.1)}

[A−]=7.0×10−3M×102.27[A^-] = 7.0 \times 10^{-3} M \times 10^{2.27}

[A−]=7.0×10−3M×157.3[A^-] = 7.0 \times 10^{-3} M \times 157.3

[A−]=1.10×10−1M[A^-] = 1.10 \times 10^{-1} M

This means that the concentration of $OH ^{-}$ that dissociates is $1.10 \times 10^{-1} M$.

Conclusion

In conclusion, hexamethylenetetramine is a weak organic base that partially dissociates in water to produce hydroxide ions ($OH ^{-}$). By using the Henderson-Hasselbalch equation, we can calculate the amount of $OH ^{-}$ that dissociates in a solution of hexamethylenetetramine. This calculation is important in understanding the chemical properties of hexamethylenetetramine and its behavior as a weak base.

References

  • "Hexamethylenetetramine" by Wikipedia
  • "The Chemistry of Hexamethylenetetramine" by Journal of Chemical Education
  • "The Henderson-Hasselbalch Equation" by Chemistry LibreTexts

Further Reading

  • "Weak Bases" by Chemistry LibreTexts
  • "pH and pKa" by Chemistry LibreTexts
  • "The Chemistry of Organic Bases" by Journal of Chemical Education
    Frequently Asked Questions about Hexamethylenetetramine ===========================================================

Q: What is hexamethylenetetramine?

A: Hexamethylenetetramine, also known as methenamine, is a weak organic base with the chemical formula $\left(\left( CH _2\right)_6 N_4\right)$. It is a colorless crystalline solid that is highly soluble in water.

Q: What are the chemical properties of hexamethylenetetramine?

A: Hexamethylenetetramine is a weak base, meaning that it does not completely dissociate in water. It has a pKa value of around 6.1, which indicates that it is a relatively weak base compared to other organic bases.

Q: What is the pH of a hexamethylenetetramine solution?

A: A $7.0 \times 10^{-3} M$ solution of hexamethylenetetramine has a pH of 8.37. This indicates that the solution is slightly alkaline, with a pH that is higher than neutral (pH 7).

Q: How does hexamethylenetetramine behave as a weak base?

A: As a weak base, hexamethylenetetramine will partially dissociate in water to produce hydroxide ions ($OH ^{-}$). The amount of $OH ^{-}$ that dissociates can be calculated using the Henderson-Hasselbalch equation.

Q: What is the Henderson-Hasselbalch equation?

A: The Henderson-Hasselbalch equation is a mathematical formula that relates the pH of a solution to the concentrations of the weak acid and its conjugate base. It is given by:

pH=pKa+log⁡[A−][HA]pH = pK_a + \log \frac{[A^-]}{[HA]}

Q: How do I calculate the amount of $OH ^{-}$ that dissociates?

A: To calculate the amount of $OH ^{-}$ that dissociates, you can use the Henderson-Hasselbalch equation and rearrange it to solve for $[A^-]$:

[A−]=[HA]×10(pH−pKa)[A^-] = [HA] \times 10^{(pH - pK_a)}

Q: What is the concentration of $OH ^{-}$ that dissociates in a hexamethylenetetramine solution?

A: The concentration of $OH ^{-}$ that dissociates is $1.10 \times 10^{-1} M$.

Q: What are some common applications of hexamethylenetetramine?

A: Hexamethylenetetramine has several common applications, including:

  • As a disinfectant and antiseptic
  • As a preservative in pharmaceuticals and cosmetics
  • As a component in the manufacture of plastics and resins
  • As a catalyst in chemical reactions

Q: Is hexamethylenetetramine safe to handle?

A: Hexamethylenetetramine is generally considered safe to handle, but it should be handled with care and in a well-ventilated area. It can be irritating to the skin and eyes, and it can cause respiratory problems if inhaled in large quantities.

Q: Where can I find more information about hexamethylenetetramine?

A: You can find more information about hexamethylenetetramine in various scientific journals and online resources, including Wikipedia, Chemistry LibreTexts, and the Journal of Chemical Education.