금속 이온에 대한 붕사 구슬 시험

붕사 융합으로 형성된 유색 유리 구슬로 전이 금속 확인하기

Qualitative Analysis Intermediate (High School) 45 분 ~$8.00

목표

전이 금속 이온이 붕사(사붕산나트륨) 유리 구슬에 융합될 때 나타내는 특징적인 색으로 전이 금속 이온을 확인한다.

배경

The borax bead test is an elegant method for identifying transition metal ions. When borax (Na₂B₄O₇·10H₂O) is heated, it loses water and forms a clear glassy bead of sodium metaborate. When a metal salt is dissolved into this bead, the metal ions become trapped in the glass matrix, producing characteristic colors. The color often differs between the oxidizing flame (outer cone) and reducing flame (inner cone), providing additional diagnostic information.

안전 경고

  • Molten borax beads are extremely hot
  • Chromium compounds are irritants — avoid dust inhalation
  • Do not touch hot beads — let cool on a watch glass
  • Cobalt compounds are toxic if ingested

필수 개인 보호 장비

goggles gloves lab_coat

재료

  • Borax (Na₂B₄O₇·10H₂O) (5 g)
    Powdered
  • Metal salt samples (0.5 g each)
    CuSO₄, CoCl₂, NiCl₂, FeCl₃, MnCl₂, Cr₂O₃
  • Unknown metal salt (0.5 g)

장비

Platinum wire loop (or nichrome alternative) Bunsen burner Forceps Watch glasses (7)

실험 절차

1

Make a small loop at the end of the platinum wire. Heat the loop in the hottest part of the flame until red-hot.

2 분 Wire is very hot
2

Dip the hot wire into powdered borax. Return to the flame and heat until a clear, transparent glass bead forms. Repeat dipping and heating if needed to build up the bead.

5 분
3

Touch the hot bead to a tiny amount of CuSO₄ powder. Return to the oxidizing flame (outer cone). Observe the color (should be blue-green).

5 분
4

Now heat the same bead in the reducing flame (inner cone, blue). The color may change to red (metallic copper).

3 분
5

Make fresh beads and repeat for each metal salt. Record colors in both oxidizing and reducing flames, both hot and cold.

20 분
6

Test the unknown salt and match the bead colors to your reference chart.

10 분

예상 결과

Cu: blue-green (oxidizing), red (reducing). Co: deep blue (both). Ni: gray-brown (oxidizing), gray (reducing). Fe: yellow-brown (oxidizing), green (reducing). Mn: violet (oxidizing), colorless (reducing). Cr: green (both, darker in reducing).

정리

Allow all beads to cool completely. Dispose of transition metal waste appropriately. Clean the platinum wire by fusing with fresh borax until clear.

세부 정보

카테고리
Qualitative Analysis
난이도
Intermediate (High School)
소요 시간
45 분
예상 비용
$8.00
단계
6
재료
3

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 미지 물질 확인 도전 75 min 불꽃 발광 분광 분석 60 min pH 지시약 무지개 45 min

Frequently Asked Questions

What is the objective of 금속 이온에 대한 붕사 구슬 시험?
전이 금속 이온이 붕사(사붕산나트륨) 유리 구슬에 융합될 때 나타내는 특징적인 색으로 전이 금속 이온을 확인한다.
How difficult is 금속 이온에 대한 붕사 구슬 시험?
This experiment is rated as Intermediate (High School). It takes approximately 45 minutes to complete.
What safety precautions are needed for 금속 이온에 대한 붕사 구슬 시험?
Key safety precautions include: Molten borax beads are extremely hot; Chromium compounds are irritants — avoid dust inhalation; Do not touch hot beads — let cool on a watch glass.
What materials are needed for 금속 이온에 대한 붕사 구슬 시험?
The main materials required are: Borax (Na₂B₄O₇·10H₂O), Metal salt samples, Unknown metal salt.
What results should I expect from 금속 이온에 대한 붕사 구슬 시험?
Cu: blue-green (oxidizing), red (reducing). Co: deep blue (both). Ni: gray-brown (oxidizing), gray (reducing). Fe: yellow-brown (oxidizing), green (reducing). Mn: violet (oxidizing), colorless (reducing). Cr: green (both, darker in reducing).