2023年1月30日 · Indicators are substances whose solutions change color due to changes in pH. These are called acid-base indicators. They are usually weak acids or bases, but their conjugate base or acid forms have different colors due to differences in their absorption spectra.

Chemical indicator, any substance that gives a visible sign, usually by a color change, of the presence or absence of a threshold concentration of a chemical species, such as an acid or an alkali in a solution. The indicator changes color when it reaches a critical range of values.

2019年7月15日 · A chemical indicator is a substance that undergoes a distinct observable change when conditions in its solution change. This could be a color change, precipitate formation , bubble formation, temperature change, or other measurable quality.

2023年10月20日 · Indicators are weak acids or weak bases that show a change in color as the concentration of Hydrogen ions in a solution changes or the pH of a solution changes. The indicators dissociate slightly in the water to form ions. Some examples of indicators are Litmus, Turmeric, Phenolphthalein, etc.

2024年11月3日 · Use our notes to learn what an indicator is for IGCSE Chemistry. Revise how universal indicator is used to measure the pH of a solution.

Indicators are substances that change colour when they are added to acidic or alkaline solutions. Universal indicator is the indicator most commonly used in the...

The chemical indicator is a substance that provides a clear sign or indication by a color change of the presence or absence of a threshold concentration of a chemical species such as an acid or base in a solution.

2023年6月28日 · In chemistry, chemical indicators are substances that undergo a distinct observable change when exposed to certain conditions, often related to the presence of acids or bases. The most common change is a color shift, but olfactory indicators, which respond by altering scent, are also used.

2025年1月27日 · An indicator is a large organic molecule that works somewhat like a " color dye". Whereas most dyes do not change color with the amount of acid or base present, there are many molecules, known as acid - base indicators, which do respond to a change in the hydrogen ion concentration. Most of the indicators are themselves weak acids.

2024年12月17日 · In the realm of chemistry, an indicator is a substance that changes color in response to a specific chemical change or reaction. Indicators are commonly used to detect the presence or absence of a particular substance, track the progress of a chemical reaction, or monitor the pH level of a solution.