Question

bromine, a liquid at room temperature, has a boiling point of $58^{circ}c$ and a melting point of $-7.2^{circ}c$. bromine can be classified as a\
mixture.\
impure substance.\
pure substance.\
compound.

Explanation:

A pure substance has a fixed melting and boiling point. Bromine has a specific boiling point (58°C) and melting point (-7.2°C), so it's a pure substance. A mixture has variable properties, an impure substance would have a range of melting/boiling points, and bromine is an element (not a compound, which is made of two or more elements).

Answer:

C. pure substance