Question

which of the following is not a solution?brasscarbon dioxideairsea water

Explanation:

A solution is a homogeneous mixture. Brass is a solid - solid homogeneous mixture (an alloy), air is a gas - gas homogeneous mixture, and seawater is a liquid - liquid (and liquid - solid) homogeneous mixture. Carbon dioxide (\(CO_2\)) is a pure compound, not a mixture.

Answer:

Carbon dioxide