Which of the following is an example of a pure substance?a.airb.table saltc.lemon juiced.milk

The example of a pure substance from the options given is b. table salt.

Here's why:

A pure substance is a form of matter that has a constant composition and properties that are constant throughout the sample. It is composed of only one type of particle. Elements and compounds are examples of pure substances.

a. Air - Air is not a pure substance. It is a mixture of different gases like nitrogen, oxygen, carbon dioxide, and others.

b. Table Salt - Table salt, or sodium chloride (NaCl), is a pure substance. It is a compound made up of sodium and chlorine and has a constant composition.

c. Lemon Juice - Lemon juice is not a pure substance. It is a mixture of water, citric acid, and other substances.

d. Milk - Milk is not a pure substance. It is a mixture of water, fat, protein, and other substances.