What color does universal indicator show at pH 9?

• A. Red
• B. Green
• C. Blue
• D. Purple

Answer: (C)

Universal indicator changes color across the pH scale because it’s a blend of dyes that respond to different hydrogen ion levels. As the solution becomes more basic (higher pH), the color shifts from red through green and into blue and purple. At pH 9, the solution is mildly basic, so the indicator shows blue—the color associated with basic conditions in the universal indicator range. Green sits around neutral (pH ~7), blue covers roughly pH 8–10, and purple appears at higher basicity, so blue is the best match for pH 9.