Which of the following indicators would show a basic solution keeping its color?

• A. Turn red
• B. Remain blue
• C. Turn green
• D. Dissolve

Answer: (B)

Indicators reveal basicity through color behavior, and blue is the hallmark color for many indicators in a basic environment. Litmus, for example, becomes blue when placed in a basic solution. If an indicator is already blue or is the blue color associated with base, it will keep that blue color rather than shifting to a different hue. So the way to signal a basic solution without a change is to observe blue remains blue. The other options describe colors you’d expect from different pH conditions or non-color changes, which don’t consistently indicate base.