The boiling point of water at standard pressure is:

## The reasoning At **standard atmospheric pressure** (which is 1 atm or 101.3 kPa at sea level), water boils at **100°C**. This is when water changes from liquid to gas (steam). The boiling point is the temperature where the vapor pressure of the liquid equals the surrounding atmospheric pressure, allowing bubbles to form throughout the liquid. This is a fundamental property you must memorize: *standard pressure = 100°C boiling point*. ## Why the wrong options tempt you **0°C** is water's *freezing/melting point*, not boiling point — students confuse these two important temperatures. **50°C** might seem "medium" but it's just warm water, not boiling. No scientific basis here, just a distractor. **200°C** is way too high — water would have evaporated long before this at standard pressure. (Though water *can* boil at higher temperatures under increased pressure, like in a pressure cooker!) ## Quick takeaway **Remember the two magic numbers for water: 0°C freezes it, 100°C boils it — both at standard pressure.**