What is the pH of 0.1 M formic acid solution? Ka=1.7„e10-4?

What is the pH value of buffer prepared by adding 60 ml of 0.1 M CH3COOH to 40 ml of a solution of 0.1 M CH3COONa? What is the pH value of an acetate buffer (pK=4.76) prepared by adding 20 ml of 1 M HCl to 100 ml of a solution of 0.3 M sodium acetate? What is the pH value of a buffer made up of 10 ml of 0.1 M NaHCO3 and 5 ml of 0.14 M H2CO3? The pKa for bicarbonate is 6.1. How would you make 1 l of a 0.1 M acetic acid buffer with a pH=4.9? The MW of acetic acid is 60 g/mole, the MW of sodium acetate is 82 g/mole. The acetate buffer is made by mixing 250 ml of 0.5 M acetic acid and 250 ml of 1 M sodium acetate. What will be the pH value of prepared buffer? The pK of acetic acid is 4.7. Calculate the pH of an acetate buffer composed of 0.2 M sodium acetate and 0.1 M acetic acid? The pKa for acetic acid is 4.76. Solve using the Henderson-Hasselbalch equation?

determine the final concentration of a 20.ml 5.M NaCl solution if 30Mml of water has is added to the solution?

I don't believe I'm in the mood to do all of your buffer homework; however, I'll be glad to help you. The formic acid is done this way. Let's call formic acid, HFo

.............HFo ==> H^+ + Fo^-
initial......0.1......0.....0
change........-x.....x......x
equil.......0.1-x.....x.....x

Ka = (H^+)(Fo^-)/(HFo)
Substitute from the ICE chart above into the Ka expression and solve for x.

For ALL of the buffer problems use the Henderson-Hasselbalch equation. Substitute into pH = pKa + log[(base)/(acid)]

5M x (20/50) = ? ASSUMING that the volumes are additive; i.e., that 20 mL + 30 mL = 50 mL. Not all solutions are additive.

To find the pH values of different solutions and buffers mentioned, we can use the Henderson-Hasselbalch equation, which is:

pH = pKa + log ([A-]/[HA])

where pH is the desired pH value, pKa is the acid dissociation constant, [A-] is the concentration of the conjugate base, and [HA] is the concentration of the acid.

It's important to note that the Henderson-Hasselbalch equation assumes that the acid and its conjugate base are the only significant sources of hydrogen ions (H+).

Let's go through each question and calculate the pH values step by step:

1. pH of 0.1 M formic acid solution:
The Ka value for formic acid is provided as 1.7 x 10^-4. Since formic acid is a monoprotic acid, the pKa value is equal to the pKa value. Using the Henderson-Hasselbalch equation, we can calculate the pH:

pH = -log10(1.7 x 10^-4)

2. pH value of buffer prepared by adding 60 ml of 0.1 M CH3COOH to 40 ml of a solution of 0.1 M CH3COONa:
Since both CH3COOH and CH3COONa are present in the buffer, we can calculate the pH using the Henderson-Hasselbalch equation. The pKa value of acetic acid (CH3COOH) is usually given as 4.76:

pH = 4.76 + log ([CH3COONa]/[CH3COOH])

3. pH value of an acetate buffer prepared by adding 20 ml of 1 M HCl to 100 ml of a solution of 0.3 M sodium acetate:
Again, using the Henderson-Hasselbalch equation, we can calculate the pH for this acetate buffer. The pK value of acetic acid is given as 4.76:

pH = 4.76 + log ([CH3COONa]/[CH3COOH])

4. pH value of a buffer made up of 10 ml of 0.1 M NaHCO3 and 5 ml of 0.14 M H2CO3:
This buffer contains both NaHCO3 (sodium bicarbonate) and H2CO3 (carbonic acid). The pKa value for bicarbonate is given as 6.1. We can calculate the pH using the Henderson-Hasselbalch equation:

pH = 6.1 + log ([NaHCO3]/[H2CO3])

5. To make a 1 L of a 0.1 M acetic acid buffer with a pH = 4.9:
We need to determine the required amounts of acetic acid (CH3COOH) and sodium acetate (CH3COONa) to achieve the desired pH of 4.9. Since the pKa for acetic acid is given as 4.7, we can rearrange the Henderson-Hasselbalch equation to solve for the ratio of [A-]/[HA]:

[A-]/[HA] = 10^(pH - pKa)

Once we have the ratio, we can use it to calculate the amount of each component needed based on their molecular weights.

6. pH value of a buffer prepared by mixing 250 ml of 0.5 M acetic acid and 250 ml of 1 M sodium acetate:
This buffer is already prepared by mixing acetic acid and sodium acetate in the given volumes and concentrations. We can use the Henderson-Hasselbalch equation to calculate the pH using the pK value of acetic acid as 4.7:

pH = 4.7 + log ([CH3COONa]/[CH3COOH])

7. pH of an acetate buffer composed of 0.2 M sodium acetate and 0.1 M acetic acid using the Henderson-Hasselbalch equation:
Similar to previous examples, we can calculate the pH using the Henderson-Hasselbalch equation and the provided pKa value for acetic acid (4.76):

pH = 4.76 + log ([CH3COONa]/[CH3COOH])

By substituting the given concentrations of sodium acetate and acetic acid into the equation, we can calculate the pH.