The boiling point of water is dependent on the atmospheric pressure. On Earth, water boils at 100 degrees Celsius at sea level, where the atmospheric pressure is approximately 1 atmosphere (atm). However, Mars has a much thinner atmosphere compared to Earth, resulting in a significantly lower atmospheric pressure.
On Mars, the atmospheric pressure is around 0.6% of Earth's atmospheric pressure, which is roughly 0.006 atmospheres (atm). As a result, water on Mars would boil at a lower temperature compared to Earth.
The exact boiling point of water on Mars can be calculated using the Clausius-Clapeyron equation, which relates the boiling point of a substance to its vapor pressure at a given temperature. However, for a rough estimation, we can refer to a simplified rule of thumb: the boiling point of water on Mars is roughly 10 degrees Celsius lower than its boiling point on Earth.
Therefore, on Mars, water would boil at approximately 90 degrees Celsius, assuming the atmospheric pressure remains constant. It's important to note that this value is an approximation and may vary depending on local conditions and altitude on Mars.