Who discovered the element chlorine?

Wilhelm Scheele

The correct answer is option 4. Wilhelm Scheele.

Carl Wilhelm Scheele, a Swedish chemist, is credited with the discovery of the element chlorine. Scheele first isolated chlorine in 1774. He achieved this by reacting hydrochloric acid (HCl) with manganese dioxide (MnO₂). This reaction released chlorine gas, and Scheele identified and described the distinct characteristics of this new substance.

Scheele's work laid the foundation for the understanding of chlorine's properties, and his contributions significantly contributed to the early development of the field of chemistry. It's important to note that although Scheele discovered chlorine independently, the element was later named by Sir Humphry Davy in 1810.