CHCOOHaq
CHCOOHaq refers to formic acid when it is dissolved in water. Formic acid has the chemical formula HCOOH. In aqueous solution, it exists primarily as HCOOH molecules, but it can also partially dissociate into a formate ion (HCOO-) and a hydronium ion (H3O+). This dissociation makes aqueous formic acid an acidic solution. The concentration of these species in solution depends on the initial concentration of formic acid and the pH of the solution. Formic acid is the simplest carboxylic acid and is a colorless liquid. It is found naturally in the venom of ants and is used industrially as a preservative and in various chemical processes. When dissolved in water, its properties are characteristic of a weak acid. The "aq" in CHCOOHaq is a chemical shorthand indicating that the substance is in an aqueous solution.