碳酸氫鹽指示劑

Bicarbonate indicator (英語：Hydrogencarbonate indicator/Bicarbonate indicator) is a chemical substance that easily absorbs carbon dioxide and is used in photosynthesis and Breathing Test whether carbon dioxide is released during the experiment. When the bicarbonate indicator is purple, the carbon dioxide concentration is less than 0.04%; when the indicator is red, the carbon dioxide concentration is approximately =0.04% (that is, the content of carbon dioxide in atmosphere); when the bicarbonate indicator is red, the carbon dioxide concentration is approximately 0.04%. When the salt indicator turns yellow, it proves that carbon dioxide with a concentration higher than 0.04% has been measured.

Composition

This solution is composed of two solutions A and B:

• Solution A: 0.02 g Thymol Blue and 0.01 g Cresol Red dissolved in 2 ml of Ethanol
• Solution B: 0.8 g sodium bicarbonate and 7.48 g potassium chloride dissolved in 90 ml distilled water

Mix A and B agents and dilute them with distilled water in a ratio of 9:1000 to obtain the bicarbonate indicator.

反應

二氧化碳濃度	< 0.04%	= 0.04%	> 0.04%
顏色	紫色	紅色	黃色