What is a gaseous mixture? 1) air 2) mixture of hydrogen and oxygen 3) alcohol solution 4) oil

A mixture differs from a complex substance in that it can be separated by physical means. In a mixture, substances retain their chemical and physical properties.
Alcohol solution is liquid. Oil is a mixture of liquid hydrocarbons. But the mixture of hydrogen and oxygen is gas, because hydrogen and oxygen are gases. The gas mixture is air, but in this mixture there are more varieties of gases: 78% is nitrogen gas, 21% is oxygen gas and 1% is accounted for by other gases – carbon dioxide, inert, carbon monoxide, nitrogen oxides, sulfur, etc.