Carbon monoxide and carbon dioxide have

3. different chemical properties and the same physical properties

Physical properties:  

Both carbon monoxide and carbon dioxide are gases. So physically, the two compounds have no fixed shape and volume and their molecules are far apart.  Therefore, they have similar physical properties.

Chemical properties:

The compounds or molecules given are different.  They will combine chemically in diverse ways.Carbon Dioxide (CO₂) is a chemical compound consisting of one carbon atom and two oxygen atoms while Carbon Monoxide (CO) is a chemical compound which contains one carbon atom and one oxygen atom.CO is also a colorless and odorless gas while CO₂ is entirely human-made and is not naturally present in the atmosphere.Thus, both gases are chemically different.

Therefore, option 3 is correct.

Learn more:

link

How do we find the answer?