Answer : The chemical property of methane is, Oxidizes in air.
Explanation :
Physical property : It can be observed or measured when no changes occurs in the chemical composition of the substance.
For example : color, boiling point, melting point, odor, density, etc.
Chemical property : It can be observed or measured when changes occurs by the chemical reaction in the composition of the substance.
For example : oxidation, combustion, toxicity, rusting, etc.
From the given options, methane oxidizes in the air shows the chemical property. While the other options, colorless, odorless and boiling point shows the physical property.
When methane react with oxygen to produce carbon dioxide and water.
Therefore, the correct answer is, Oxidize in air.