Question: Assume that a small open cup of concentrated hydrochloric acid is placed inside the glass dome at this moment. What new phenomenon is most likely to be observed?
A. White solid particles will form in the air.
B. The liquid in the right-hand cup will rapidly darken.
C. The liquid in the left-hand cup will turn colorless again.
D. A large number of bubbles will be produced in the left-hand cup.
Clues:
1. The image shows a three-stage experiment involving two beakers of liquid.
2. In the first stage, both beakers contain a clear, colorless liquid.
3. In the second stage, the beakers are placed under a glass dome, and the liquid in the left beaker develops a pink layer on its surface.
4. In the third stage, the pink color in the left beaker intensifies and spreads.
5. The pink color is characteristic of a phenolphthalein indicator in a basic solution.
6. The experiment demonstrates that a volatile substance (a gas) is being released from the right beaker, diffusing through the air, and dissolving in the left beaker, causing a chemical change. This volatile substance must be a base, like ammonia.
Answer: C
Category: Chemistry