Question

1. Write the balanced chemical equation for the reaction of HF with water.

Type your answer here.

2. What is the pH and concentration of F^– in a 0.100M solution of HF?                                                        Ans. pH = 2.10

Insert your work image here.

3. Write the balanced chemical equation for the dissolution of NaF in water.

Type your answer here.

4. What would happen if the equilibrium [F^–] that you calculated in 2 was changed by adding 0.00500 moles of solid NaF to 100.0 mL of the solution? (If equilibrium has already been established, which direction is the reaction going to “shift” to re-establish equilibrium after the addition of solid NaF?)

Type your answer here.

5. Determine the pH of the solution in 4.  Assume that the addition of solid NaF does not change the volume of solution.

                                                                                                                                                                Ans. pH = 2.88

Insert your work image here.

6. What is the name of this type of solution?

Type your answer here.

7. If a small amount of a strong acid, like HNO₃, is added to our HF/F⁻ buffer solution, which of the buffer components (HF or F⁻) will react to neutralize the added acid.

Type your answer here.

8. Using the Henderson-Hasselbalch equation, determine the pH of the solution from 5 AFTER 10.0 mL of 0.100M HNO₃ is added.           Ans. pH = 2.73

Insert your work image here.

9. If a small amount of a strong base, like KOH, is added to our HF/F⁻ buffer solution, which of the buffer components (HF or F⁻) will react to neutralize the added acid.

Type your answer here.

10. Using the Henderson-Hasselbalch equation, determine the pH of the solution from 5 AFTER 10.0 mL of 0.100M KOH is added.          Ans. pH = 3.00

Insert your work image here.

11. How many moles of strong acid could you reasonably expect to add to the solution in 5 before the pH would change drastically (by 1.00 pH units)?   Ans. About 0.0036 mol

Type your answer here.

12. How many moles of strong base could you reasonably expect to add to the solution in 5 before the pH would change drastically (by 1.00 pH units)?  Ans. About 0.0086 mol

Type your answer here.

Answer 1

1 HF +0,0 - 420t+F- moderatele HF is wathe solution acting like strong and. It is because HR + H₂02 H₂ot to which is undissociated Then. I- tHE = HE As you con soo large apinity of f-to to won't allow it to dissociate the ka CHE). (6.604 104) is strongly furouring reactants. So hf in 40 isn't buffy because there isnt almost any &- to be considered as a conjugate aid. So, if you add some and there will not be enough F for it houbalisation.