Chemistry Liquids NUMS 2023
PMDC Verified Question 30 of 73
When 2 ice cubes are pressed over each other they unite to form one cube due to:
A
Dipole-dipole attraction
B
Covalent attraction
C
Van Der Waal's forces
D
H – bonding
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option D: H – bonding
Concept:

The phenomenon of ice cubes fusing together under mechanical pressure is known as regelation. It relies on the unique thermal and structural properties of water's solid lattice.

Formula:

Not applicable.

Solution:

  • When severe pressure is applied to ice, its melting point locally decreases, causing a microscopic layer of water to temporarily melt at the contact boundary between the two cubes.


  • Once the external pressure is released, this thin layer of liquid water rapidly refreezes.


  • During refreezing, the water molecules perfectly realign their partial charges to form rigid, highly stable Hydrogen bonds across the boundary, seamlessly stitching the two distinct cubes into a single continuous crystal lattice.


Why other options are incorrect:

Water's entire solid state structure is governed specifically by hydrogen bonding, not generic dipole or Van der Waals forces. Covalent bonds strictly hold the O and H together within the individual molecule, not between different molecules.

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