Which among the following halogen exists in liquid state at room temperature?

Bromine

The correct answer is Option (3) → Bromine

The halogen that exists in the liquid state at room temperature is Bromine.

Here is a detailed explanation of the physical states of the halogens at room temperature (approximately 25°C):

1. Fluorine (F₂)

Physical State: Gas at room temperature.

Properties: Fluorine is the most reactive halogen and exists as a pale yellow gas at room temperature.

2. Chlorine (Cl₂)

Physical State: Gas at room temperature.

Properties: Chlorine exists as a yellow-green gas under normal conditions.

3. Bromine (Br₂)

Physical State: Liquid at room temperature.

Properties: Bromine is the only non-metal that is liquid at room temperature. It is a reddish-brown liquid with a strong, unpleasant odor. Its melting point is -7.2°C, and its boiling point is 58.8°C, meaning it stays liquid in the range of typical room temperatures.

4. Iodine (I₂)

Physical State: Solid at room temperature.

Properties: Iodine is a solid with a metallic luster and a dark purple-black color at room temperature. It sublimates to form a violet gas when heated.

Summary:

Bromine is the halogen that exists in the liquid state at room temperature.