pH 지시약 무지개

전체 pH 범위에 걸친 지시약 색 변화 지도 만들기

Qualitative Analysis Beginner (Middle School) 45 분 ~$8.00

목표

다양한 pH 지시약이 특정 pH 값에서 어떻게 색이 변하는지 관찰하고 지시약 변색 범위의 개념을 이해한다.

배경

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.

안전 경고

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

필수 개인 보호 장비

goggles lab_coat

재료

  • 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

장비

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

실험 절차

1

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

10 분 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 분
3

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

5 분
4

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

5 분
5

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

5 분
6

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

15 분

예상 결과

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.

정리

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

세부 정보

카테고리
Qualitative Analysis
난이도
Beginner (Middle School)
소요 시간
45 분
예상 비용
$8.00
단계
6
재료
6

더 많은 실험

탄수화물의 아이오딘-전분 시험 30 min 할로겐에 대한 베이슈타인 시험 25 min 음이온 확인 시험 60 min 침전에 의한 양이온 확인 90 min 비누 용액으로 경수 시험 40 min 식물 색소의 크로마토그래피 60 min 금속 이온에 대한 붕사 구슬 시험 45 min 미지 물질 확인 도전 75 min 불꽃 발광 분광 분석 60 min

Frequently Asked Questions

What is the objective of pH 지시약 무지개?
다양한 pH 지시약이 특정 pH 값에서 어떻게 색이 변하는지 관찰하고 지시약 변색 범위의 개념을 이해한다.
How difficult is pH 지시약 무지개?
This experiment is rated as Beginner (Middle School). It takes approximately 45 minutes to complete.
What safety precautions are needed for pH 지시약 무지개?
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 pH 지시약 무지개?
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 pH 지시약 무지개?
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.