钾焰色反应

通过紫丁香/紫色火焰鉴定钾

Flame Tests Beginner (Middle School) 20 分钟 ~$6.00

目标

观察钾离子产生的紫丁香/紫色火焰，学习使用钴蓝玻璃区分钾与钠污染。

背景

Potassium produces a pale lilac or violet flame when heated. The emission occurs at 766.5 nm and 769.9 nm (near-infrared/deep red doublet). Because the flame is quite faint and easily overwhelmed by sodium's intense yellow, cobalt blue glass is used as a filter to block sodium emission and reveal potassium's true color.

安全警告

  • Wear safety goggles at all times
  • Keep hair tied back near open flames
  • Handle HCl with care

所需PPE

goggles lab_coat

材料

  • Potassium chloride (KCl) (1 g)
  • Hydrochloric acid (HCl) (10 mL)
    1M concentration
  • Cobalt blue glass (1 piece)
    For filtering sodium light

设备

Bunsen burner Nichrome wire loop Watch glass Forceps

步骤

1

Clean the nichrome wire thoroughly by dipping in HCl and heating.

2 分钟
2

Place potassium chloride on the watch glass and collect a sample on the clean wire.

1 分钟
3

Hold the sample in the Bunsen burner flame. Observe with the naked eye first.

2 分钟
4

Now observe the flame through cobalt blue glass to filter out any sodium contamination.

2 分钟
5

Record the difference in appearance with and without the cobalt blue glass filter.

2 分钟

预期结果

Without the filter, you may see a faint lilac color possibly masked by yellow from sodium impurities. Through the cobalt blue glass, a clear violet/lilac flame should be visible as the glass absorbs the yellow sodium emission.

清理

Clean the wire loop with HCl. Return cobalt blue glass to storage.

详情

类别
Flame Tests
难度
Beginner (Middle School)
时长
20 分钟
预估费用
$6.00
步骤数
5
材料
3

更多实验

焰色反应对比实验 45 min 钙焰色反应 15 min 钠焰色反应 15 min 钡焰色反应 20 min 铜焰色反应 15 min 锂焰色反应 15 min 锶焰色反应 15 min

Frequently Asked Questions

What is the objective of 钾焰色反应?
观察钾离子产生的紫丁香/紫色火焰，学习使用钴蓝玻璃区分钾与钠污染。
How difficult is 钾焰色反应?
This experiment is rated as Beginner (Middle School). It takes approximately 20 minutes to complete.
What safety precautions are needed for 钾焰色反应?
Key safety precautions include: Wear safety goggles at all times; Keep hair tied back near open flames; Handle HCl with care.
What materials are needed for 钾焰色反应?
The main materials required are: Potassium chloride (KCl), Hydrochloric acid (HCl), Cobalt blue glass.
What results should I expect from 钾焰色反应?
Without the filter, you may see a faint lilac color possibly masked by yellow from sodium impurities. Through the cobalt blue glass, a clear violet/lilac flame should be visible as the glass absorbs the yellow sodium emission.