The colour of zinc sulphide is

The colour of $ZnS$ is white.

Zinc sulphide (ZnS) is a compound that is commonly known for its white color. Here's why:

Zinc Sulphide's Color

• Zinc Sulphide (ZnS) typically appears white in its pure form. This white color is a result of the way the compound interacts with light.
• Zinc sulphide is commonly used in luminescent materials, and when it is subjected to ultraviolet (UV) light, it can emit a glow, but under normal conditions, it is white.

Why the Other Options Are Incorrect

• Option B (Black): Zinc sulphide is not typically black. The black color might appear in cases where it is impure or mixed with other compounds, but pure zinc sulphide is white.
• Option C (Brown): Brown is not the natural color of zinc sulphide. Some transition metal compounds can appear brown, but not zinc sulphide.
• Option D (Red): Zinc sulphide is not red under normal conditions. While some sulfur compounds can show a red color, zinc sulphide does not exhibit this characteristic.

Summary

The color of pure zinc sulphide (ZnS) is white. This property makes it a useful material in various applications such as phosphors and semiconductors. Therefore, the correct answer is Option A (White).