Converting the Volume to Milliliters

Oct 13, 2025 by wbrum.org 121 views

Hydrofluoric Acid and Sodium Hydroxide Titration: Calculating the Volume of Sodium Hydroxide Needed

In chemistry, titration is a laboratory technique used to determine the concentration of a substance in a solution. One of the most common types of titration is acid-base titration, where a strong acid is titrated with a strong base. In this article, we will discuss the titration of hydrofluoric acid (HF) with sodium hydroxide (NaOH) using the following reaction:

${ HF(aq) + OH^{-}(aq) \rightarrow F^{-}(aq) + H_2O(l) }$

The reaction between hydrofluoric acid and sodium hydroxide is a classic example of an acid-base reaction. Hydrofluoric acid is a weak acid, meaning it does not completely dissociate in water, while sodium hydroxide is a strong base that completely dissociates in water. The reaction between the two substances produces water and fluoride ions.

To calculate the volume of sodium hydroxide needed to titrate a given volume of hydrofluoric acid, we need to use the concept of stoichiometry. Stoichiometry is the study of the quantitative relationships between reactants and products in chemical reactions.

In this case, we are given the concentration of hydrofluoric acid (0.425 M) and the volume of the solution (35.0 mL). We are also given the concentration of sodium hydroxide (0.250 M). We need to calculate the volume of sodium hydroxide needed to titrate the given volume of hydrofluoric acid.

Step 1: Calculate the Number of Moles of Hydrofluoric Acid

To calculate the number of moles of hydrofluoric acid, we need to multiply the concentration of the solution (in moles per liter) by the volume of the solution (in liters).

${ \text{Number of moles of HF} = \text{Concentration of HF} \times \text{Volume of HF} }$

${ \text{Number of moles of HF} = 0.425 \, \text{M} \times 0.0350 \, \text{L} }$

${ \text{Number of moles of HF} = 0.014875 \, \text{mol} }$

Step 2: Calculate the Number of Moles of Sodium Hydroxide Needed

To calculate the number of moles of sodium hydroxide needed, we need to use the concept of stoichiometry. Since the reaction between hydrofluoric acid and sodium hydroxide is a 1:1 reaction, the number of moles of sodium hydroxide needed is equal to the number of moles of hydrofluoric acid.

${ \text{Number of moles of NaOH needed} = \text{Number of moles of HF} }$

${ \text{Number of moles of NaOH needed} = 0.014875 \, \text{mol} }$

Step 3: Calculate the Volume of Sodium Hydroxide Needed

To calculate the volume of sodium hydroxide needed, we need to divide the number of moles of sodium hydroxide needed by the concentration of the solution (in moles per liter).

${ \text{Volume of NaOH needed} = \frac{\text{Number of moles of NaOH needed}}{\text{Concentration of NaOH}} }$

${ \text{Volume of NaOH needed} = \frac{0.014875 \, \text{mol}}{0.250 \, \text{M}} }$

${ \text{Volume of NaOH needed} = 0.0595 \, \text{L} }$

Converting the Volume to Milliliters

To convert the volume from liters to milliliters, we need to multiply the volume in liters by 1000 (since there are 1000 milliliters in 1 liter).

${ \text{Volume of NaOH needed (mL)} = \text{Volume of NaOH needed (L)} \times 1000 }$

${ \text{Volume of NaOH needed (mL)} = 0.0595 \, \text{L} \times 1000 }$

${ \text{Volume of NaOH needed (mL)} = 59.5 \, \text{mL} }$

In this article, we discussed the titration of hydrofluoric acid with sodium hydroxide using the following reaction:

${ HF(aq) + OH^{-}(aq) \rightarrow F^{-}(aq) + H_2O(l) }$

We calculated the volume of sodium hydroxide needed to titrate 35.0 mL of 0.425 M hydrofluoric acid using the concept of stoichiometry. The results showed that 59.5 mL of 0.250 M sodium hydroxide are needed to titrate the given volume of hydrofluoric acid.

CRC Handbook of Chemistry and Physics, 95th ed., CRC Press, 2014.
Chemistry: An Atoms First Approach, 2nd ed., Steven S. Zumdahl, Cengage Learning, 2014.
General Chemistry: Principles and Modern Applications, 11th ed., John W. Hill, William S. Lach, Richard D. Wixom, Pearson Education, 2014.
Hydrofluoric Acid and Sodium Hydroxide Titration: Q&A

In our previous article, we discussed the titration of hydrofluoric acid with sodium hydroxide using the following reaction:

${ HF(aq) + OH^{-}(aq) \rightarrow F^{-}(aq) + H_2O(l) }$

We calculated the volume of sodium hydroxide needed to titrate 35.0 mL of 0.425 M hydrofluoric acid using the concept of stoichiometry. In this article, we will answer some frequently asked questions about the titration of hydrofluoric acid with sodium hydroxide.

Q: What is the purpose of titration in chemistry?

A: Titration is a laboratory technique used to determine the concentration of a substance in a solution. It involves adding a known amount of a substance (the titrant) to a solution of unknown concentration until the reaction is complete.

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, producing a high concentration of hydrogen ions. Examples of strong acids include hydrochloric acid (HCl) and sulfuric acid (H2SO4). A weak acid, on the other hand, is an acid that only partially dissociates in water, producing a lower concentration of hydrogen ions. Hydrofluoric acid (HF) is an example of a weak acid.

Q: Why is sodium hydroxide used as a titrant in the titration of hydrofluoric acid?

A: Sodium hydroxide (NaOH) is a strong base that completely dissociates in water, producing a high concentration of hydroxide ions. It is used as a titrant in the titration of hydrofluoric acid because it reacts with the hydrofluoric acid to produce water and fluoride ions.

Q: What is the significance of the 1:1 stoichiometry in the reaction between hydrofluoric acid and sodium hydroxide?

A: The 1:1 stoichiometry in the reaction between hydrofluoric acid and sodium hydroxide means that one mole of hydrofluoric acid reacts with one mole of sodium hydroxide to produce one mole of water and one mole of fluoride ions. This means that the number of moles of sodium hydroxide needed to titrate a given volume of hydrofluoric acid is equal to the number of moles of hydrofluoric acid.

Q: How can the concentration of hydrofluoric acid be determined using the titration method?

A: The concentration of hydrofluoric acid can be determined using the titration method by measuring the volume of sodium hydroxide needed to titrate a given volume of hydrofluoric acid. The concentration of hydrofluoric acid can then be calculated using the formula:

${ \text{Concentration of HF} = \frac{\text{Number of moles of HF}}{\text{Volume of HF}} }$

Q: What are some common applications of the titration of hydrofluoric acid with sodium hydroxide?

A: The titration of hydrofluoric acid with sodium hydroxide is commonly used in various applications, including:

Analysis of hydrofluoric acid in industrial processes: The titration method is used to determine the concentration of hydrofluoric acid in industrial processes, such as the production of aluminum and other metals.
Determination of fluoride ions in water: The titration method is used to determine the concentration of fluoride ions in water, which is an important parameter in water quality analysis.
Analysis of hydrofluoric acid in biological samples: The titration method is used to determine the concentration of hydrofluoric acid in biological samples, such as blood and urine.

In this article, we answered some frequently asked questions about the titration of hydrofluoric acid with sodium hydroxide. We discussed the purpose of titration in chemistry, the difference between strong and weak acids, and the significance of the 1:1 stoichiometry in the reaction between hydrofluoric acid and sodium hydroxide. We also discussed some common applications of the titration of hydrofluoric acid with sodium hydroxide.