Which one among the following is called philosopher's wool?

Correct Option

Zinc oxide (ZnO) is traditionally known as philosopher's wool. It is a white, fluffy powder obtained when zinc metal is combusted in air. Alchemists historically referred to it by this name due to its wool-like appearance and its association with early chemical experiments.

Key applications of zinc oxide include:

• As a UV-blocking agent in sunscreens and cosmetics.
• As a white pigment in paints (known as zinc white).
• In the production of ceramics and glass.
• In medical ointments and creams for its antiseptic and astringent properties.

Incorrect Options

Options (a) Zinc bromide, (b) Zinc nitrate, and (d) Zinc chloride are various zinc salts. These compounds do not possess the characteristic physical properties or historical association to be termed "philosopher's wool." The term specifically refers to zinc oxide (ZnO).