Question

visual reading tool: buffers
the figure below shows what happens to the ph of two solutions when an acid is added. use the key above the image to answer the questions about the image.

image with experiment 1 and experiment 2, ph scale from base to neutral to acid

1. in experiment 1, does adding an acid to a basic solution result in an acid or a base? ______
2. in experiment 2, does adding an acid to a basic solution result in an acid or a base? ______
3. in which experiment is the acid added to a buffered base? how can you tell?

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Explanation:

Question 1

Step1: Analyze Experiment 1's color change

The initial solution is basic (darker shade), adding acid. The final color is still in the basic - neutral - acid scale but ends as a base (darker, not acidic). So adding acid to basic here still results in base.

Step1: Analyze Experiment 2's color change

Initial basic solution, add acid. Final color is light (acidic side). So adding acid to basic here results in acid.

Step1: Recall buffer behavior

A buffer resists pH change. In Experiment 1, adding acid to basic solution doesn't change to acid (resists pH shift towards acid), so it's a buffered base. In Experiment 2, pH changes to acid (no buffering).

Step2: Justify based on color

Experiment 1: Final solution is still basic (color shows base - neutral range), so pH didn't drop to acid, meaning buffer resisted. Experiment 2: Final is acid, so no buffer.

Answer:

Base

Question 2