BioMedical Admissions Test (BMAT) 2026 – 400 Free Practice Questions to Pass the Exam

When an indicator is added to a strong base, the color observed is typically blue. This is because many common indicators, such as litmus and phenolphthalein, change to a blue color in basic (alkaline) conditions.

In the case of litmus, it starts red in acidic solutions and turns blue when it encounters basic solutions. Similarly, phenolphthalein is colorless in acidic solutions and turns pink or blue in the presence of strong bases. The basic environment has a higher pH, which is conducive to the color change of the indicator to blue.

This understanding is rooted in the chemical properties of acids and bases, specifically how they interact with pH indicators. The significance of color change provides a useful visual cue in identifying the nature of a solution – in this case, confirming the presence of a strong base through the indication of blue color.