이중 지시약을 이용한 탄산염-중탄산염 혼합물 적정

두 가지 지시약으로 탄산염 혼합물 분석하기

Titrations Advanced (University) 55 분 ~$14.00

목표

페놀프탈레인과 메틸 오렌지 두 가지 지시약을 순서대로 사용하여 HCl로 탄산나트륨과 탄산수소나트륨 혼합물을 분석한다.

배경

A mixture of Na₂CO₃ and NaHCO₃ has two equivalence points when titrated with acid. Phenolphthalein detects the first (CO₂³⁻ → HCO₃⁻), and methyl orange detects the second (HCO₃⁻ → H₂CO₃). By comparing the volumes at each endpoint, the individual concentrations can be calculated.

안전 경고

  • HCl is corrosive
  • Wear safety goggles throughout
  • Handle indicators carefully — they stain

필수 개인 보호 장비

goggles lab_coat

재료

  • Sodium carbonate/bicarbonate mixture (100 mL)
    Unknown composition
  • Hydrochloric acid (HCl) (100 mL)
    0.1M standardized
  • Phenolphthalein indicator (5 mL)
  • Methyl orange indicator (5 mL)
  • Distilled water (200 mL)

장비

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

실험 절차

1

Pipette 25.0 mL of the carbonate/bicarbonate mixture into the flask.

2 분
2

Add 2-3 drops of phenolphthalein. The solution should turn pink.

1 분
3

Fill the burette with 0.1M HCl. Record the initial volume.

3 분
4

Titrate until the pink color disappears (first endpoint). Record volume V₁.

10 분
5

Without refilling the burette, add 2-3 drops of methyl orange to the same flask.

1 분
6

Continue titrating until the color changes from yellow to orange/salmon (second endpoint). Record total volume V₂.

10 분
7

Repeat the entire process for concordant results.

18 분
8

Calculate: V(phenolphthalein) = V₁, V(methyl orange only) = V₂ - V₁. Use these to find the individual concentrations of Na₂CO₃ and NaHCO₃.

7 분

예상 결과

V₁ corresponds to the carbonate content, and (V₂ - V₁) includes both the remaining carbonate reaction and the original bicarbonate. For pure carbonate, V₂ - V₁ = V₁. Any excess indicates bicarbonate present.

정리

Neutralize waste solutions before disposal. Rinse all glassware thoroughly.

세부 정보

카테고리
Titrations
난이도
Advanced (University)
소요 시간
55 분
예상 비용
$14.00
단계
8
재료
5

더 많은 실험

페놀프탈레인을 이용한 산염기 적정 45 min 과망간산칼륨 산화환원 적정 50 min 표백제의 아이오딘 적정 50 min 전도도 적정 50 min 제산제 정제의 역적정 60 min 메틸 오렌지를 이용한 산염기 적정 40 min 침전 적정(모어법) 45 min 아이오딘을 이용한 비타민 C 적정 40 min EDTA 착화 적정을 이용한 물 경도 측정 45 min pH 적정 곡선 50 min

Frequently Asked Questions

What is the objective of 이중 지시약을 이용한 탄산염-중탄산염 혼합물 적정?
페놀프탈레인과 메틸 오렌지 두 가지 지시약을 순서대로 사용하여 HCl로 탄산나트륨과 탄산수소나트륨 혼합물을 분석한다.
How difficult is 이중 지시약을 이용한 탄산염-중탄산염 혼합물 적정?
This experiment is rated as Advanced (University). It takes approximately 55 minutes to complete.
What safety precautions are needed for 이중 지시약을 이용한 탄산염-중탄산염 혼합물 적정?
Key safety precautions include: HCl is corrosive; Wear safety goggles throughout; Handle indicators carefully — they stain.
What materials are needed for 이중 지시약을 이용한 탄산염-중탄산염 혼합물 적정?
The main materials required are: Sodium carbonate/bicarbonate mixture, Hydrochloric acid (HCl), Phenolphthalein indicator, Methyl orange indicator, Distilled water.
What results should I expect from 이중 지시약을 이용한 탄산염-중탄산염 혼합물 적정?
V₁ corresponds to the carbonate content, and (V₂ - V₁) includes both the remaining carbonate reaction and the original bicarbonate. For pure carbonate, V₂ - V₁ = V₁. Any excess indicates bicarbonate present.