Question

The figure below shows the titration curve of a weak acid (HA) with a strong base (such as NaOH). Identify the species that has the greatest effect on the pH of the solution at each stage of the titration. 14 12 10 8 6 4 2 0 Volume of strong base (mL) A A- B OH- C HA D ratio A-/HA Part 2 (0.3 point) A chemist titrates a 25.0 mL sample of 0.218 M benzoic acid (C6H5COOH) against a 0.100 M solution of NaOH. The overall reaction is shown by the equation below: C6H5COOH(aq) + NaOH(aq) -> C6H5COONa(aq) + H2O(l) The Ka value for benzoic acid is 6.28 x 10^-5. Calculate the pH at the start of the titration, before any NaOH has been added. Give your answer correctly to two places after the decimal. Part 3 (0.3 point) What will the pH be when 12.0 mL of 0.100 M NaOH has been added to the weak acid solution? Give your answer to two places after the decimal.

          The figure below shows the titration curve of a weak acid (HA) with a strong base (such as NaOH). Identify the species that has the greatest effect on the pH of the solution at each stage of the titration.
14
12
10
8
6
4
2
0
Volume of strong base (mL)
A A-
B OH-
C HA
D ratio A-/HA
Part 2 (0.3 point)
A chemist titrates a 25.0 mL sample of 0.218 M benzoic acid (C6H5COOH) against a 0.100 M solution of NaOH.
The overall reaction is shown by the equation below:
C6H5COOH(aq) + NaOH(aq) -> C6H5COONa(aq) + H2O(l)
The Ka value for benzoic acid is 6.28 x 10^-5. Calculate the pH at the start of the titration, before any NaOH has been added. Give your answer correctly to two places after the decimal.
Part 3 (0.3 point)
What will the pH be when 12.0 mL of 0.100 M NaOH has been added to the weak acid solution? Give your answer to two places after the decimal.

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The figure below shows the titration curve of a weak acid (HA) with a strong base (such as NaOH). Identify the species that has the greatest effect on the pH of the solution at each stage of the titration.
14
12
10
8
6
4
2
0
Volume of strong base (mL)
A A-
B OH-
C HA
D ratio A-/HA
Part 2 (0.3 point)
A chemist titrates a 25.0 mL sample of 0.218 M benzoic acid (C6H5COOH) against a 0.100 M solution of NaOH.
The overall reaction is shown by the equation below:
C6H5COOH(aq) + NaOH(aq) -> C6H5COONa(aq) + H2O(l)
The Ka value for benzoic acid is 6.28 x 10^-5. Calculate the pH at the start of the titration, before any NaOH has been added. Give your answer correctly to two places after the decimal.
Part 3 (0.3 point)
What will the pH be when 12.0 mL of 0.100 M NaOH has been added to the weak acid solution? Give your answer to two places after the decimal.

Added by Andrea M.

Chemistry: Structure and Properties

Nivaldo Tro 2nd Edition

Instant Answer

Solved by Expert David Collins

04/11/2022

Step 1

The pH of the solution is determined by the ionization of the weak acid. The ionization of benzoic acid can be represented by the following equation: C6H5COOH(aq) ⇌ C6H5COO-(aq) + H+(aq) The equilibrium expression for this reaction is: Ka = Show more…

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The figure below shows the titration curve of a weak acid (HA) with a strong base (such as NaOH). Identify the species that has the greatest effect on the pH of the solution at each stage of the titration: Part 2 (0.3 point) A chemist titrates a 25.0 mL sample of 0.218 M benzoic acid (C6H5COOH) against a 0.100 M solution of NaOH. The overall reaction is shown by the equation below: C6H5COOH(aq) + NaOH(aq) -> C6H5COONa(aq) + H2O(l) The Ka value for benzoic acid is 6.28 x 10^-5. Calculate the pH at the start of the titration, before any NaOH has been added. Give your answer correctly to two places after the decimal. Part 3 (0.3 point) What will the pH be when 12.0 mL of 0.100 M NaOH has been added to the weak acid solution? Give your answer to two places after the decimal.

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Transcript

00:01 First we need to identify which species predominate and determine the ph of the solution when carrying out a titration.

00:10 This is an acid being titrated with a strong base, ph, and volume of the base added.

00:23 And we have c, d, a, and b.

00:33 For a, all we have is a minus.

00:37 The conjugate base to the acid.

00:41 For b, we have excess hydroxide.

00:46 For c, we are starting out with just the weak acid.

00:51 And for d, we have both the ha and the a -minus.

00:58 Or more specifically, with the henderson -hasselbalch equation, it's the a -minus to h .a.

01:04 Ratio.

01:07 If a chemist titrates 25 milliliters of a sample of 0 .218 molar benzoic acid with 0 .1 molar sodium hydroxide, the overall reaction given.

01:19 The k -a value for benzodiaic acid is 6 .28 times 10 to negative 5.

01:25 We're asked to calculate the ph at the start of the titration.

01:29 Well, at the start of the titration, as i mentioned, all we have is h .a.

01:35 And the hydronium ion concentration is typically determined for a solution that just contains a weak acid by taking the square root of k .a.

01:47 6 .28 times 10 to the negative 5 multiplied by the concentration of the weak acid, benzoic acid is at a concentration of 0 .218.

02:02 And as long as the hydronium concentration, which we calculate to be 3 .7 times 10 to the negative 3 molar is less than 5 % of the original concentration of the acid, which it is, then this little equation is all we need to calculate the hydronium concentration...

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