Match List I with List II

Choose the correct answer from the options given below:

A-II, B-IV, C-I, D-III

The correct answer is option 4. A-II, B-IV, C-I, D-III.

Let us break down the reasoning behind each match in detail:

A. Phosphine (\(PH_3\)): II. Smoke screen

Phosphine is a colorless, toxic, and flammable gas. It can ignite spontaneously in air under certain conditions, leading to the production of dense white smoke. Because phosphine can produce dense smoke upon ignition, it has historically been used in creating smoke screens in warfare, where the smoke is used to conceal movements or positions.

B. Chlorine Water: IV. Bleaching agent

Chlorine water is a solution of chlorine gas dissolved in water. It contains hypochlorous acid (\(HClO\)) and hydrochloric acid (\(HCl\)), both of which are strong oxidizing agents. Chlorine water is widely used as a bleaching agent because it can oxidize and break down color-causing compounds, making it effective for bleaching textiles, paper, and other materials.

C. White Phosphorus :I. Catches fire in air

White phosphorus is a highly reactive allotrope of phosphorus. It is so reactive that it spontaneously ignites when exposed to air at room temperature, reacting with oxygen to form phosphorus pentoxide (\(P_4O_{10}\)).  The ability of white phosphorus to catch fire in air is a well-known and dangerous property, which is why it is stored under water to prevent exposure to air.

D. Sulfur (Monoclinic and Rhombic): III. Crown structure

Sulfur exists in various allotropes, with monoclinic and rhombic being the most common crystalline forms. These allotropes of sulfur consist of crown-shaped \(S_8\) molecules, where eight sulfur atoms are arranged in a ring structure. The characteristic crown-like ring structure of \(S_8\) is a defining feature of these allotropes.