Which of the following substances is classified as an inorganic salt?

Sodium chloride is classified as an inorganic salt because it is a compound formed from the reaction of an acid and a base, specifically hydrochloric acid (HCl) and sodium hydroxide (NaOH). Inorganic salts typically consist of positive ions (cations) and negative ions (anions) that come together to form neutral compounds, and sodium chloride is a prime example of this. It is commonly known as table salt and has a simple structure comprising sodium ions and chloride ions.

Calcium carbonate, while also a salt, is primarily characterized as a carbonate and is more frequently associated with inorganic compounds but is not categorized as a salt in the same sense as sodium chloride. Citric acid is an organic compound and does not fit the definition of an inorganic salt, as it contains carbon and is derived from organic sources. Glucose is a simple sugar and again, falls under the category of organic compounds rather than inorganic salts. Thus, sodium chloride stands out as the definitive inorganic salt among the choices presented.