Formation of Sulphur when H2S gas is passed through Nitric Acid

When hydrogen sulfide (H2S) gas is passed through nitric acid (HNO3), a chemical reaction occurs that leads to the formation of elemental sulfur (S). The type of sulfur formed in this reaction is amorphous sulfur (C).

Explanation:

The reaction between hydrogen sulfide and nitric acid can be represented by the following equation:

H2S + 4HNO3 → H2SO4 + 4NO2 + 2H2O

In this reaction, hydrogen sulfide reacts with nitric acid to produce sulfuric acid, nitrogen dioxide gas, and water. However, it is important to note that the reaction conditions, such as temperature and concentration, can influence the type of sulfur formed.

Types of Sulfur

There are several types of sulfur depending on their crystalline structure. These include:

1. Rhombic Sulfur: Rhombic sulfur is a yellow crystalline solid that consists of S8 rings. It is the most stable and common form of sulfur at room temperature.

2. Prismatic Sulfur: Prismatic sulfur is a monoclinic crystal form of sulfur. It has a needle-like appearance and is formed under specific temperature and pressure conditions.

3. Amorphous Sulfur: Amorphous sulfur lacks a definite crystalline structure and appears as a yellow powder. It is formed when sulfur cools rapidly or when sulfur vapor is condensed.

4. Monoclinic Sulfur: Monoclinic sulfur is a crystalline form of sulfur that appears as long, needle-like crystals. It is formed under specific temperature and pressure conditions.

5. Plastic Sulfur: Plastic sulfur is a unique form of sulfur that can be molded or shaped at temperatures above 96°C. It exhibits some plastic properties.

Sulfur Formed in the Reaction

In the reaction between H2S gas and nitric acid, the sulfur formed is amorphous sulfur (C). This is because the reaction conditions, such as room temperature, do not favor the formation of rhombic or prismatic sulfur. Instead, the rapid cooling of the reaction mixture leads to the formation of amorphous sulfur in the form of a yellow powder.

Therefore, the correct answer is C) amorphous sulfur.