Which indicator is colourless in acidic solution and pink in alkaline solution?
A
Litmus
B
Methyl orange
C
Universal indicator
D
Phenolphthalein
Correct Answer: Option D — Phenolphthalein
Explanation:
Phenolphthalein is colourless in acidic and neutral solutions but turns pink to magenta in alkaline solutions and is commonly used as an indicator in acid-base titrations.