Application method and phenomenon of acid - base indicator, such as colorless phenolphthalein test solution, purple litmus test solution, etc. Application method and phenomenon of acid - base indicator. such as colorless phenolphthalein test solution, purple litmus test solution, etc.

Application method and phenomenon of acid - base indicator, such as colorless phenolphthalein test solution, purple litmus test solution, etc. Application method and phenomenon of acid - base indicator. such as colorless phenolphthalein test solution, purple litmus test solution, etc.

Colorless phenolphthalein: after adding acid, the color will not be colored, and the alkali will be colored red and weak pink.
Purple litmus, acid, red, alkali, blue, but it's not very recognizable.

What color changes will occur when acid solution and alkaline solution meet with purple litmus test solution and colorless phenolphthalein test solution respectively?

Both litmus test solution and phenolphthalein test solution are acid-base indicators and can be used to test whether the solution is acidic? Or an alkaline solution?
The litmus test solution is originally purple, which turns red in case of acidic solution, blue in case of alkaline solution, and still purple in case of neutral solution.
Phenolphthalein test solution is red in case of alkaline solution, and still colorless in case of acid or neutral solution.

Both litmus test solution and phenolphthalein test solution are acid-base indicators and can be used to test whether the solution is acidic. Or an alkaline solution?
The litmus test solution is originally purple, which turns red in case of acidic solution, blue in case of alkaline solution, and still purple in case of neutral solution.
Phenolphthalein test solution is red in case of alkaline solution, and still colorless in case of acid or neutral solution.