An unknown element 'X' reacts vigorously with cold water to produce a gas 'Y' that catches fire immediately with a pop sound. The resulting solution turns phenolphthalein indicator pink. Identify 'X' and 'Y', and the nature of the resulting solution.

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A X = Copper, Y = Oxygen; Acidic solution
B X = Sodium, Y = Hydrogen; Basic solution
C X = Iron, Y = Hydrogen; Neutral solution
D X = Magnesium, Y = Carbon dioxide; Basic solution

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Answer: B. X = Sodium, Y = Hydrogen; Basic solution

Highly reactive metals like sodium (Na) react violently even with cold water. This exothermic reaction produces sodium hydroxide (NaOH) and releases hydrogen gas (Hz), which is highly flammable and burns with a characteristic "pop" sound. Because sodium hydroxide is a strong base, it changes the colour of the phenolphthalein indicator from colourless to a vibrant pink.

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An unknown element 'X' reacts vigorously with cold water to produce a gas 'Y' that catches fire immediately with a pop sound. The resulting solution turns phenolphthalein indicator pink. Identify 'X' and 'Y', and the nature of the resulting solution.

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