Which of the following is an example of a qualitative test in chemistry?

• A. Observing the color change when phenolphthalein is added to a solution
• B. Measuring the mass of a precipitate formed in a reaction
• C. Calculating the pH of a solution using a pH meter
• D. Determining the concentration of NaCl in water using titration

Answer: (A)

Verified step by step guidance

1. Understand the difference between qualitative and quantitative tests in chemistry. Qualitative tests provide descriptive information about the presence or characteristics of a substance, such as color, odor, or texture, without involving numerical measurements.
2. Recognize that quantitative tests involve measuring numerical values, such as mass, volume, concentration, or pH, to obtain precise data about a substance.
3. Analyze each option to determine if it describes a qualitative or quantitative test:
4. - Observing the color change when phenolphthalein is added to a solution is a qualitative test because it involves noting a color change, which is descriptive and non-numerical.
5. - Measuring the mass of a precipitate, calculating pH with a meter, and determining concentration by titration are quantitative tests because they involve numerical measurements.