An element Z reacts with water to form a solution which turns phenolphthalein indicator pink. The element Z is most likely to be:
Sulphur
sodium
carbon
silicon

Correct Answer: B. sodium

Explanation: Phenolphthalein is an indicator used in acid-base titrations. It turns colorless in acidic solutions and pink in basic solutions. Sodium is a metal which reacts with water to form sodium hydroxide, which is a base. Hence, phenolphthalein turns the solution pink