Which of the following is closest to the normal boiling point of iodine (I2) at 1 atm pressure?

• A. 357 °C
• B. 184 °C
• C. 100 °C
• D. 63 °C

Answer: (B)

Verified step by step guidance

1. Understand that the normal boiling point of a substance is the temperature at which its vapor pressure equals 1 atm (760 mmHg). This means the substance changes from liquid to gas at this temperature under standard atmospheric pressure.
2. Recall or look up the typical boiling points of halogens or specifically iodine (I2) from reliable data sources or tables, as boiling points are physical properties determined experimentally.
3. Compare the given options (357 °C, 184 °C, 100 °C, 63 °C) with the known boiling point of iodine to identify which is closest to the actual normal boiling point at 1 atm.
4. Note that iodine is a solid at room temperature and sublimes at about 184 °C, which is its normal boiling point under atmospheric pressure.
5. Conclude that the correct answer is the temperature closest to 184 °C, as this matches the known physical property of iodine's boiling point at 1 atm.