Arcoíris de Indicadores de pH

Mapeo de los cambios de color de indicadores en todo el rango de pH

Qualitative Analysis Beginner (Middle School) 45 min ~$8,00

Objetivo

Observar cómo diferentes indicadores de pH cambian de color a valores de pH específicos y comprender el concepto de rangos de transición de indicadores.

Antecedentes

pH indicators are weak acids or bases whose conjugate forms have different colors. Each indicator has a characteristic transition range where it changes color. By testing multiple indicators across a range of buffered solutions, students create a visual map of indicator behavior that reinforces concepts of acid-base equilibrium and the Henderson-Hasselbalch equation.

Advertencias de seguridad

  • Indicators can stain skin and clothing
  • Extreme pH solutions (pH 1, 14) are corrosive
  • Avoid mixing different buffer solutions

EPP requerido

goggles lab_coat

Materiales

  • Buffer solutions (pH 1–14) (5 mL each)
    Pre-prepared set
  • Methyl orange indicator (5 mL)
    pH 3.1–4.4 range
  • Bromothymol blue indicator (5 mL)
    pH 6.0–7.6 range
  • Phenolphthalein indicator (5 mL)
    pH 8.2–10.0 range
  • Universal indicator (5 mL)
    Full pH range
  • Litmus solution (red and blue) (5 mL each)
    Simple acid/base test

Equipamiento

Spot plate or microwell plate Dropper pipettes (one per indicator) pH meter or pH paper White background paper

Procedimiento

1

Arrange the spot plate and add 10 drops of each buffer solution (pH 1 through 14) across each row.

10 min Handle pH 1 and 14 solutions carefully
2

Add 2 drops of methyl orange to the first row of buffer solutions. Record the color at each pH.

5 min
3

Add 2 drops of bromothymol blue to the second row. Record the color at each pH.

5 min
4

Add 2 drops of phenolphthalein to the third row. Record the color at each pH.

5 min
5

Add 2 drops of universal indicator to the fourth row. Observe the full rainbow of colors.

5 min
6

Create a color chart recording each indicator's color at every pH level. Identify each indicator's transition range.

15 min

Resultados esperados

Methyl orange: red (acidic) to yellow (basic) around pH 3–4. Bromothymol blue: yellow to blue around pH 6–7.6. Phenolphthalein: colorless to pink around pH 8–10. Universal indicator: red through violet across the full pH range.

Limpieza

Pour solutions into the appropriate waste container (acid or base). Rinse spot plates thoroughly with distilled water.

Detalles

Categoría
Qualitative Analysis
Dificultad
Beginner (Middle School)
Duración
45 min
Costo estimado
$8,00
Pasos
6
Materiales
6

Más experimentos

Cromatografía de Pigmentos Vegetales 60 min Desafío de Identificación de Sustancias Desconocidas 75 min Espectroscopía de Emisión de Llama 60 min Identificación de Cationes por Precipitación 90 min Prueba de Beilstein para Halógenos 25 min Prueba de Dureza del Agua con Solución de Jabón 40 min Prueba del Almidón-Yodo para Carbohidratos 30 min Prueba de Perla de Bórax para Iones Metálicos 45 min Pruebas de Identificación de Aniones 60 min

Frequently Asked Questions

What is the objective of Arcoíris de Indicadores de pH?
Observar cómo diferentes indicadores de pH cambian de color a valores de pH específicos y comprender el concepto de rangos de transición de indicadores.
How difficult is Arcoíris de Indicadores de pH?
This experiment is rated as Beginner (Middle School). It takes approximately 45 minutes to complete.
What safety precautions are needed for Arcoíris de Indicadores de pH?
Key safety precautions include: Indicators can stain skin and clothing; Extreme pH solutions (pH 1, 14) are corrosive; Avoid mixing different buffer solutions.
What materials are needed for Arcoíris de Indicadores de pH?
The main materials required are: Buffer solutions (pH 1–14), Methyl orange indicator, Bromothymol blue indicator, Phenolphthalein indicator, Universal indicator.
What results should I expect from Arcoíris de Indicadores de pH?
Methyl orange: red (acidic) to yellow (basic) around pH 3–4. Bromothymol blue: yellow to blue around pH 6–7.6. Phenolphthalein: colorless to pink around pH 8–10. Universal indicator: red through violet across the full pH range.