Which of the following is the melting point of water at standard atmospheric pressure?

• A. 0~^ext{o}ext{C}
• B. 32~^ext{o}ext{C}
• C. 100~^ext{o}ext{C}
• D. -273~^ext{o}ext{C}

Answer: (A)

Verified step by step guidance

1. Understand that the melting point of a substance is the temperature at which it changes from solid to liquid at a given pressure, typically standard atmospheric pressure (1 atm).
2. Recall that water's melting point is a well-known physical property and is commonly used as a reference point in temperature scales.
3. Recognize that water freezes (solidifies) at 0~^\text{o}\text{C} and melts at the same temperature under standard atmospheric pressure.
4. Note that 32~^\text{o}\text{C} and 100~^\text{o}\text{C} correspond to other important temperatures for water: 32~^\text{o}\text{F} is the freezing point in Fahrenheit, and 100~^\text{o}\text{C} is the boiling point at 1 atm.
5. Understand that -273~^\text{o}\text{C} is absolute zero, the theoretical lowest temperature, unrelated to water's melting point.