Final answer:
Alcohol can either refer to a pure substance, like ethanol, or a mixture, like an alcoholic beverage. Kerosene and petrol are mixtures of alkanes, and air is a mixture of gases. Without further context, it's difficult to classify alcohol as not a mixture.
Step-by-step explanation:
The question is asking to identify which item listed is not a mixture. Kerosene, air, and petrol are all mixtures. Kerosene is a mixture of alkanes with higher molecular masses, and petrol is a liquid mixture of straight- and branched-chain alkanes, plus various additives. Air is a mixture of nitrogen, oxygen, and other gases. On the other hand, alcohol can either be a pure substance if it refers to a specific type of alcohol like ethanol or a mixture if it refers to an alcoholic beverage containing various other components. Without specifying the type of alcohol, it's difficult to determine whether option C, alcohol, is not a mixture. Typically, in chemistry, 'alcohol' refers to ethanol which is a pure substance, not a mixture, when not mixed with other components.