Titulación de Vitamina C con Yodo

Medición del contenido de ácido ascórbico en jugo de frutas

Titrations Intermediate (High School) 40 min ~$10,00

Objetivo

Determinar el contenido de vitamina C (ácido ascórbico) en jugo de frutas frescas mediante una titulación con yodo e indicador de almidón.

Antecedentes

Ascorbic acid reduces iodine to iodide ions in a 1:1 molar ratio. Starch indicator turns dark blue-black in the presence of excess iodine. When all the vitamin C is consumed, the next drop of iodine produces the blue-black color, marking the endpoint.

Advertencias de seguridad

  • Iodine stains skin and clothing
  • Wear safety goggles
  • Handle iodine solution with care

EPP requerido

goggles lab_coat

Materiales

  • Fresh orange juice (200 mL)
    Freshly squeezed preferred
  • Iodine solution (100 mL)
    0.005M
  • Starch indicator solution (10 mL)
    1% solution
  • Distilled water (200 mL)

Equipamiento

50 mL burette Burette stand and clamp 250 mL Erlenmeyer flask 25 mL pipette Pipette filler White tile

Procedimiento

1

Rinse and fill the burette with the standardized iodine solution. Record the initial volume.

3 min Iodine stains
2

Pipette 25.0 mL of orange juice into the Erlenmeyer flask.

2 min
3

Add 5 drops of starch indicator to the flask.

1 min
4

Titrate by adding iodine solution slowly while swirling. The brown iodine color will disappear as it reacts with vitamin C.

8 min
5

Near the endpoint, add drop by drop until a persistent dark blue-black color appears for 20 seconds.

3 min
6

Record the final volume and repeat for concordant results.

15 min
7

Calculate the mass of vitamin C per volume of juice. Compare with the labeled value.

5 min

Resultados esperados

Fresh orange juice typically contains 40-80 mg of vitamin C per 100 mL. The starch-iodine endpoint should be a sharp transition to blue-black. Older or heat-treated juice will show lower vitamin C content.

Limpieza

Dispose of iodine waste in designated containers. Rinse all glassware with water. Clean any iodine stains with sodium thiosulfate solution.

Detalles

Categoría
Titrations
Dificultad
Intermediate (High School)
Duración
40 min
Costo estimado
$10,00
Pasos
7
Materiales
4

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Frequently Asked Questions

What is the objective of Titulación de Vitamina C con Yodo?
Determinar el contenido de vitamina C (ácido ascórbico) en jugo de frutas frescas mediante una titulación con yodo e indicador de almidón.
How difficult is Titulación de Vitamina C con Yodo?
This experiment is rated as Intermediate (High School). It takes approximately 40 minutes to complete.
What safety precautions are needed for Titulación de Vitamina C con Yodo?
Key safety precautions include: Iodine stains skin and clothing; Wear safety goggles; Handle iodine solution with care.
What materials are needed for Titulación de Vitamina C con Yodo?
The main materials required are: Fresh orange juice, Iodine solution, Starch indicator solution, Distilled water.
What results should I expect from Titulación de Vitamina C con Yodo?
Fresh orange juice typically contains 40-80 mg of vitamin C per 100 mL. The starch-iodine endpoint should be a sharp transition to blue-black. Older or heat-treated juice will show lower vitamin C content.