Water detection and boiling point elevation Steps:

• Anhydrous copper(II) chloride (likely intended as cobalt chloride test) turns blue to pink in presence of water due to hydration.
• X and Z show color change, indicating they contain water; Y shows no change, so Y lacks water.
• Pure water boils at 100°C; non-volatile impurities raise boiling point via colligative properties (ΔT_b = K_b × m).
• X boils at 100°C (pure water), Y at 98°C (not water, lower boiling suggests different liquid), Z at 103°C (impure water, elevated boiling point).

Why C is correct:

• Matches test results (X/Z contain water, Y does not) and boiling points (100°C for pure, >100°C for impure per boiling point elevation formula).

Why the others are wrong:

• A: Y no color change, cannot be pure water.
• B: Y no color change and 98°C boiling, not impure water.
• D: Z boils at 103°C, indicating impurity, not pure water.

Final answer: C