Determine whether or not the mixing of each pair of solutions results in a buffer. c. 55.0 mL of 0.15 M HF; 85.0 mL of 0.10 M NaF

Verified step by step guidance

1. Identify the components of the solutions: HF is a weak acid and NaF is its conjugate base.
2. Calculate the moles of HF using the formula: moles = concentration \( \times \) volume. Convert the volume from mL to L before calculation.
3. Calculate the moles of NaF using the same formula: moles = concentration \( \times \) volume. Again, convert the volume from mL to L before calculation.
4. Determine if the solution can act as a buffer: A buffer solution contains a weak acid and its conjugate base in significant amounts.
5. Compare the moles of HF and NaF to ensure both are present in significant amounts to resist changes in pH, confirming the presence of a buffer.

Key Concepts

Buffer Solutions

A buffer solution is a system that resists changes in pH upon the addition of small amounts of acid or base. It typically consists of a weak acid and its conjugate base or a weak base and its conjugate acid. In this case, HF (hydrofluoric acid) is a weak acid, and NaF (sodium fluoride) provides the conjugate base, F-. Together, they can form a buffer solution.

Weak Acids and Conjugate Bases

Weak acids are substances that partially dissociate in solution, establishing an equilibrium between the undissociated acid and its ions. The conjugate base is formed when the weak acid donates a proton (H+). In the given example, HF partially dissociates to produce H+ and F-, making NaF a source of F-, which can react with added H+ to maintain pH stability.

Henderson-Hasselbalch Equation

The Henderson-Hasselbalch equation is a mathematical formula used to calculate the pH of a buffer solution. It is expressed as pH = pKa + log([A-]/[HA]), where [A-] is the concentration of the conjugate base and [HA] is the concentration of the weak acid. This equation helps determine if the given concentrations of HF and NaF will effectively create a buffer by assessing their ratio.