Question

Formal Lab Report- Analysis of Acid by Titration with Sodium Hydroxidez Topic - Titration.

Answer 1

Note: The main aim of analysis of acid Titration is to find out the average concentration of an unknown acid.

Answer 2

Formal Lab Report: Analysis of an Acid by Titration with Sodium Hydroxide

Title:

Determination of Acetic Acid Concentration in Vinegar via Titration with NaOH

Objective:

To determine the molarity of acetic acid (CH₃COOH) in a vinegar sample using a standardized sodium hydroxide (NaOH) solution through acid-base titration.

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1. Introduction

• Titration Principle: A technique where a solution of known concentration (NaOH) is used to determine the concentration of an unknown acid (CH₃COOH).

• Key Reaction:

  $${\text{CH}}_3\text{COOH}+\text{NaOH}\to {\text{CH}}_3{\text{COO}}^{-}+{\text{Na}}^{+}+{\text{H}}_2\text{O}$$

• Endpoint Detection: Phenolphthalein indicator (colorless in acid → pink in base).

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2. Materials & Methods

Materials:

• Burette, pipette, Erlenmeyer flask, phenolphthalein, 0.1 M NaOH, vinegar sample.

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Procedure:

1. Standardize NaOH (if not pre-standardized) using potassium hydrogen phthalate (KHP).

2. Dilute vinegar 1:10 with distilled water.

3. Titrate: Add NaOH to vinegar + indicator until faint pink persists (~30 sec).

4. Repeat 3 times for accuracy.

5. 
   

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3. Data & Calculations

Sample Data Table:

Trial	Volume NaOH (mL)	Volume Vinegar (mL)
1	22.5	10.0
2	22.3	10.0

Calculations:

1. Average NaOH volume:

   $$\frac{22.5+22.3}{2}=22.4\text{mL}$$

2. Moles of NaOH:

   $$0.1\text{M}\times 0.0224\text{L}=0.00224\text{mol}$$

3. Moles of CH₃COOH (1:1 stoichiometry):

   $$0.00224\text{mol}$$

4. Molarity of CH₃COOH in vinegar:

   $$\frac{0.00224\text{mol}}{0.010\text{L}}=0.224\text{M}$$

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4. Results & Discussion

• Result: The vinegar sample contained 0.224 M acetic acid.

• Error Sources:

• Burette reading inaccuracies.

• Over-titration (pink too dark).

• Compare to Label: Commercial vinegar is typically ~0.85 M (5% w/v); dilution factor confirms accuracy.

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5. Conclusion

The titration method successfully determined the acetic acid concentration, demonstrating its reliability for acid analysis.