Listening practice test, Grades 8–9 — question 19 of 27
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Cabbage Juice Lab
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Ms. Perez: Okay, everyone. Today we're using red cabbage juice to test whether liquids are acids or bases. Each group has four cups labeled A through D.
Ms. Perez: First, put on your goggles. Over your eyes, not on your forehead. Next, pour about two spoonfuls of cabbage juice into each cup. Then add one liquid to each cup: lemon juice in A, water in B, baking soda mixed with water in C, and vinegar in D.
Ms. Perez: Watch the color. If it turns pink or red, the liquid is an acid. If it turns green or blue, it's a base. If it stays purple, it's close to neutral. Write the color in your table before you touch anything else. And nobody rinses a cup in the sink until I've come around and checked your table.
Choose the best answer.
Why does Ms. Perez most likely want to check the tables before anyone rinses a cup?
You can move on without answering. Unanswered questions are counted as wrong.