# Chemistry help pliz

posted by .

Explain (using equations) how a solution of 1.0 mol dm^-3 in both CH3COOH and CH3COONa is resistant to changes n pH when we add either small amounts of acid or small amount of base (such solution is called a buffer)

• Chemistry help pliz -

continued from above calculate the initial pH of the acetic acid-sodium acetate solution above.The pKa of acetic acid is 4.76

• Chemistry help pliz -

To do the second part from first principles. Start with the acid dissociation equation:

HAc -> H+ + Ac-

Ka is then

[H+][Ac-]/[HAc]

at the start

HAc -> H+ + Ac-

1.0 M ___0__1.0M

at the end

HAc -> H+ + Ac-
1.0-x__x___1.0+x

so Ka is
Ka=(x)(1.0+x)/(1.0-x)

we can treat this in two ways, we can solve for x

or

Assume that x is small so that

Ka=x(1.0)/(1.0)=x

thus pKa = pH =4.76

• Chemistry help pliz -

To give another perspective, you can calculate the pH of a buffer using the Henderson-Hasselbalch equation.

## Similar Questions

1. ### chemistry-

How do I construct an ICE table for this question. CH3COOH + NaOH --> CH3COONa + H2O Fill in the equilibrium line of the table. [Think about the initial pH and think about the pH at the end point of the titration. Initial pH 2.72 …
2. ### Chemistry

Commercial vinegar was titrated with NaOH solution to determine the content of acetic acid, HC2H3O2. For 20.0 milliliters of the vinegar 26.7 milliliters of 0.600-molar NaOH solution was required. What was the concentration of acetic …
3. ### chemistry

Please judge my answer: Question: 24 mL of 0.39 mol/L acetic acid is titrated with a standardized 0.33 mol/L KOH solution. Calculate the pH of the solution after 17 mL of the KOH solution has been added. Assume the Ka of acetic acid …
4. ### Chemistry

You are carrying out the titration of 100.0 mL of 1.000M acetic acid with 1.000 M sodium hydroxide. Ka = 1.76x10^-5 of acetic acid. (a) Calculate the initial pH of your acetic acid sample. (b) Calculate the pH of the solution after …
5. ### chemistry

A. Strong Base 1.) What is the concentration of a solution of KOH for which the pH is 11.89?
6. ### Chemistry

A buffer solution is prepared by dissolving 0.400 mol of CH3COOH and 0.200 mol of CH3COONa in 1.00 L of water. 1.00 mL of 10.0 M HCl is added to a 100 mL portion of this solution. What is the final pH of the resulting solution?
7. ### Chemistry

A buffer solution is prepared by dissolving 0.400 mol of CH3COOH and 0.200 mol of CH3COONa in 1.00 L of water. 1.00 mL of 10.0 M HCl is added to a 100 mL portion of this solution. What is the final pH of the resulting solution?
8. ### Chemistry

Sodium methanoate, NaHCOO, and methanoic acid, HCOOH, can be used to make a buffer solution. Explain how this combination resists changes in pH when small amounts of acid or base are added. Buffers kind of confuse me and I'm not sure …
9. ### Chemistry

A buffer is made by mixing 100 mL of 0.25 M acetic acid (CH3COOH) and 150 mL of 0.10 M sodium acetate (CH3COONa). Calculate the pH of the solution after 0.5g of solid NaOH is added to the solution (Given Ka (CH3COOH) =1.8 x 10-5)
10. ### Chemistry

Find the ratio of the pH of solution (I) containing 1 mol of CH3COONa and 1 mol of HCl in 1L and solution (II) containing 1 mol of CH3COONa and 1 mol of CH3COOH in 1L

More Similar Questions