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CHEM 104 Homework 6 1. 20 points-Ch. 18.1, 19.2 A chemist is testing the propert

ID: 1029409 • Letter: C

Question

CHEM 104 Homework 6 1. 20 points-Ch. 18.1, 19.2 A chemist is testing the properties of a newly-discovered pair of acids, A1 and A2. She determines them both to be monoprotic and performs several experiments to compare their acid strength . 19.9 in textbook) to 1.0 M aqueous solutions of each acid results in a yellow color for A1 and a green-blue color for A2. .Experiment 2: Measuring the conductivity of the same two solutions results in a higher Experiment 1: Adding a few drops of bromophenol blue (see Fig measurement for A1 than for A2 Experiment 3: Addition of a Zn strip to each solution resulted in vigorous bubbling in the case of A1 and mild bubbling in the case of A2. . Based on these experiments, which is the stronger acid? Explain how the results of each experiment support your choice, and also identify the gas inside the bubbles in Experiment 3.

Explanation / Answer

A1 is stronger than A2.

# bromothymol blue exhibit yellow color below the pH 6 and blue for pH above 7.6. So the yellow color for A1 indicates that its pH is less than 6 and green-blue color indicates the pH of A2 is just above 6. Thus A1 is a stronger acid than A2

# From the conductivity measurements, acid A1 exhibit higher conductivity than A2. Since A1 is strong acid than A2, its dissociation will be greater resulted in the higher conductivity.

# Reaction with metallic Zn, it liberates hydrogen gas. In the case of strong acid, the liberation of H2 will be vigorous and in weak acid exhibit mild bubbling.

From the 3 experiments, it is clear that A1 is stronger than A2.