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According to Wikipedia:

The atmospheric pressure on the Martian surface averages 600 pascals (0.087 psi; 6.0 mbar), about 0.6% of Earth's mean sea level pressure of 101.3 kilopascals (14.69 psi; 1.013 bar).

This chart seems to indicate that the 77°F (25°C) water would be above its boiling point by more than 75°F (the granularity of the chart does not give more info).

This would result in a (perhaps explosive) boiling of the pool until it had released enough energy to be below its boiling point in the 6°F to -24°F (-14°C to -31°C) range. At this point the remaining water may freeze and sublimate in the future.

But, according to Wikipedia, the surface of Mars is between -226°F (-143°C) and 95F (35°C), so depending on conditions the pool may never cool below its boiling point, and all of it simply evaporates.

@Dean MacGregor correctly points out that at 600Pa water will never be a stable liquid, so the final result (after 'explosive' boiling) will eventually be that all the water evaporates, or a portion boils off, allowing the remainder to cool to ice, which may or may not sublimate. All depending largely on the temperature of this particular part of Mars.

According to Wikipedia:

The atmospheric pressure on the Martian surface averages 600 pascals (0.087 psi; 6.0 mbar), about 0.6% of Earth's mean sea level pressure of 101.3 kilopascals (14.69 psi; 1.013 bar).

This chart seems to indicate that the 77°F (25°C) water would be above its boiling point by more than 75°F (the granularity of the chart does not give more info).

This would result in a (perhaps explosive) boiling of the pool until it had released enough energy to be below its boiling point in the 6°F to -24°F (-14°C to -31°C) range. At this point the remaining water may freeze and sublimate in the future.

But, according to Wikipedia, the surface of Mars is between -226°F (-143°C) and 95F (35°C), so depending on conditions the pool may never cool below its boiling point, and all of it simply evaporates.

@Dean MacGregor correctly points out that at 600Pa water will never be a stable liquid, so the final result (after 'explosive' boiling) will eventually be that all the water evaporates, or a portion boils off, allowing the remainder to cool to ice, which may or may not sublimate. All depending largely on the temperature of this particular part of Mars.

As a demonstration, this is a video of water being subjected to a vacuum at room temperature. On those conditions the water boils, until it cools to freezing.

The pressure on the surface of Mars according to https://en.wikipedia.org/wiki/Atmosphere_of_Mars is

The atmospheric pressure on the Martian surface averages 600 pascals (0.087 psi; 6.0 mbar), about 0.6% of Earth's mean sea level pressure of 101.3 kilopascals (14.69 psi; 1.013 bar).

This chart http://www.engineersedge.com/h2o_boil_pressure.htm seems to indicate that the 77F (25C) water would be above its boiling point by more than 75F (the granularity of the chart does not give more info).

This would result in a (perhaps explosive) boiling of the pool until it had released enough energy to be below its boiling point in the 6F to -24F (-14C to -31C) range. At this point the remaining water may freeze and sublimate in the future.

BUT, according to https://en.wikipedia.org/wiki/Mars the surface of Mars is between -226F (-143C) and 95F (35C), so depending on conditions the pool may never cool below its boiling point, and all of it simply evaporates.

Edit @Dean MacGregor correctly points out that at 600Pa water will never be a stable liquid, so the final result (after 'explosive' boiling) will eventually be that all the water evaporates, or a portion boils off, allowing the remainder to cool to ice, which may or may not sublimate. All depending largely on the temperature of this particular part of Mars

According to Wikipedia:

The atmospheric pressure on the Martian surface averages 600 pascals (0.087 psi; 6.0 mbar), about 0.6% of Earth's mean sea level pressure of 101.3 kilopascals (14.69 psi; 1.013 bar).

This chart seems to indicate that the 77°F (25°C) water would be above its boiling point by more than 75°F (the granularity of the chart does not give more info).

This would result in a (perhaps explosive) boiling of the pool until it had released enough energy to be below its boiling point in the 6°F to -24°F (-14°C to -31°C) range. At this point the remaining water may freeze and sublimate in the future.

But, according to Wikipedia, the surface of Mars is between -226°F (-143°C) and 95F (35°C), so depending on conditions the pool may never cool below its boiling point, and all of it simply evaporates.

@Dean MacGregor correctly points out that at 600Pa water will never be a stable liquid, so the final result (after 'explosive' boiling) will eventually be that all the water evaporates, or a portion boils off, allowing the remainder to cool to ice, which may or may not sublimate. All depending largely on the temperature of this particular part of Mars.

The pressure on the surface of Mars according to https://en.wikipedia.org/wiki/Atmosphere_of_Mars is

The atmospheric pressure on the Martian surface averages 600 pascals (0.087 psi; 6.0 mbar), about 0.6% of Earth's mean sea level pressure of 101.3 kilopascals (14.69 psi; 1.013 bar).

This chart http://www.engineersedge.com/h2o_boil_pressure.htm seems to indicate that the 77F water would be above its boiling point by more than 75F (the granularity of the chart does not give more info).

This would result in a (perhaps explosive) boiling of the pool until it had released enough energy to be below its boiling point in the 6F to -24F range. At this point the remaining water may freeze and sublimate in the future.

BUT, according to https://en.wikipedia.org/wiki/Mars the surface of Mars is between -226F and 95F, so depending on conditions the pool may never cool below its boiling point, and all of it simply evaporates.

Edit @Dean MacGregor correctly points out that at 600Pa water will never be a stable liquid, so the final result (after 'explosive' boiling) will eventually be that all the water evaporates, or a portion boils off, allowing the remainder to cool to ice, which may or may not sublimate. All depending largely on the temperature of this particular part of Mars

The pressure on the surface of Mars according to https://en.wikipedia.org/wiki/Atmosphere_of_Mars is

The atmospheric pressure on the Martian surface averages 600 pascals (0.087 psi; 6.0 mbar), about 0.6% of Earth's mean sea level pressure of 101.3 kilopascals (14.69 psi; 1.013 bar).

This chart http://www.engineersedge.com/h2o_boil_pressure.htm seems to indicate that the 77F (25C) water would be above its boiling point by more than 75F (the granularity of the chart does not give more info).

This would result in a (perhaps explosive) boiling of the pool until it had released enough energy to be below its boiling point in the 6F to -24F (-14C to -31C) range. At this point the remaining water may freeze and sublimate in the future.

BUT, according to https://en.wikipedia.org/wiki/Mars the surface of Mars is between -226F (-143C) and 95F (35C), so depending on conditions the pool may never cool below its boiling point, and all of it simply evaporates.

Edit @Dean MacGregor correctly points out that at 600Pa water will never be a stable liquid, so the final result (after 'explosive' boiling) will eventually be that all the water evaporates, or a portion boils off, allowing the remainder to cool to ice, which may or may not sublimate. All depending largely on the temperature of this particular part of Mars