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Q70 (CDS-II/2012) Science & Technology › Basic Science (Physics, Chemistry, Biology) › Thermal physics Answer Verified

When ice melts, its

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Your answer:  ·  Correct: A
Explanation

When ice melts, its volume decreases while its mass remains constant. Water exhibits an anomalous property where it expands upon freezing, creating an open crystalline structure with low packing efficiency. Consequently, ice is less dense than liquid water. Upon melting at 0 °C, this structure collapses, and the molecules move closer together, leading to a volume reduction of approximately 9%. According to the principle of conservation of mass, the total amount of matter remains unchanged during a phase transition. While most substances expand upon melting, water's unique hydrogen-bonding network causes it to shrink as it transitions from solid to liquid. Therefore, the mass is conserved while the volume decreases, making the resulting liquid water denser than the initial ice.

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