Ice and water are placed in a closed container at a pressure of 1 atm and temperature 273.15 K . If pressure of the system is increased 2 times, keeping temperature constant, then identify correct observation from following

Ice and water are at 273.15 K and 1 atm in a closed container, and the pressure is increased to 2 atm while keeping the temperature constant.

Water has an unusual property: its solid-liquid boundary line in the phase diagram has a negative slope, which means that increasing pressure at constant temperature near the melting point favors the liquid phase.

At 273.15 K and 1 atm, ice and water coexist at the normal melting point. When the pressure is raised to 2 atm at the same temperature, the melting point of ice decreases with increasing pressure due to the negative slope of the solid-liquid equilibrium line. Thus at 2 atm the melting point lies below 273.15 K, so the system at 273.15 K is entirely in the liquid phase.

The solid phase (ice) will therefore melt completely and disappear. The correct answer is Option 2: The solid phase (ice) disappears completely.