Ice melts faster in saltwater compared to freshwater due to the phenomenon of freezing point depression. When a solute, such as salt, is added to water, it lowers the freezing point of the water. The freezing point of saltwater is lower than that of freshwater.
In order for ice to melt, it needs to absorb enough heat to raise its temperature above its melting point. When ice is in contact with freshwater, the heat from the surroundings is transferred to the ice, raising its temperature. However, when ice is in contact with saltwater, the lower freezing point of the saltwater causes the ice to start melting at a lower temperature than it would in freshwater.
As a result, the ice in saltwater absorbs heat more readily from the surroundings, causing it to melt faster compared to ice in freshwater. The dissolved salt in the water disrupts the ice lattice and weakens its structure, making it easier for the ice to melt and transition into liquid water.