Tincture of iodine is a commonly used antiseptic solution consisting of 2-3% iodine dissolved in a mixture of alcohol and water. The alcohol acts as a carrier, enhancing the penetration of iodine, which provides the antimicrobial action. Elimination of other options:
Iodoform (\( \text{CHI}_3 \)): A yellow crystalline compound with antiseptic properties but not related to tincture.
2-Iodopropane and Iodobenzene: These are organic iodides used in various chemical reactions but are not antiseptic solutions.
Hence, the correct description of tincture of iodine is "2-3% iodine solution in alcohol-water."
Final Answer: \[ \boxed{\text{2-3\% iodine solution in alcohol-water}} \]
A balloon filled with an air sample occupies \( 3 \, \text{L} \) volume at \( 35^\circ \text{C} \). On lowering the temperature to \( T \), the volume decreases to \( 2.5 \, \text{L} \). The temperature \( T \) is: [Assume \( P \)-constant]