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For an interesting experiment, write down what scientific truth the experiment proves. urgent! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !

Use beakers to hold clear dilute hydrochloric acid, sodium hydroxide solution, and salt water respectively. Then prepare the clarified purple cabbage water.

Put an appropriate amount of purple cabbage water into dilute hydrochloric acid, sodium hydroxide solution, and salt water respectively. The solutions will appear red, blue, and purple respectively.

Scientific reason: Purple cabbage contains a chemical called anthocyanin, which turns red when exposed to acid and blue when exposed to alkali, but does not change color in neutral solutions. Explain that dilute hydrochloric acid, sodium hydroxide solution, and salt water are acidic, alkaline, and neutral respectively.