What is the formula for nitrite?

The formula for nitrite is represented as NO2-. This ion consists of one nitrogen atom and two oxygen atoms, carrying a negative charge. Nitrite is derived from nitric acid (HNO3) by removing one oxygen atom; thus, it serves as a key intermediate in the nitrogen cycle and in various biological processes.

The other choices represent different chemical species: NO3- is the nitrate ion, which has one additional oxygen atom compared to nitrite and carries a negative charge as well. HCO3- is the bicarbonate ion, which is different in both composition and charge. C2H3O2- is the acetate ion, which is a completely different structure involving carbon, hydrogen, and oxygen. Understanding these differences is essential when identifying chemical species and their corresponding formulas.