If universal indicator shows red, the solution is?

If universal indicator shows red, the solution is?

• A. Strong acid
• B. Weak acid
• C. Neutral
• D. Weak alkali

Answer: (A)

Universal indicator tells you how acidic or basic a solution is by color, which corresponds to its pH. Red shows a very acidic solution, with a pH around 1–2. A strong acid completely dissociates in water, giving a high concentration of hydrogen ions and a very low pH, so red is the expected color. Neutral solutions sit around green (pH about 7), while weak acids would appear more orange or yellow, indicating a higher pH than a strong acid. Alkalis, with high pH, show blue to purple colors. So red points to a strong acid.

Universal indicator tells you how acidic or basic a solution is by color, which corresponds to its pH. Red shows a very acidic solution, with a pH around 1–2. A strong acid completely dissociates in water, giving a high concentration of hydrogen ions and a very low pH, so red is the expected color. Neutral solutions sit around green (pH about 7), while weak acids would appear more orange or yellow, indicating a higher pH than a strong acid. Alkalis, with high pH, show blue to purple colors. So red points to a strong acid.