Final answer:
The orbitals used to form each indicated bond in citric acid are determined by the Lewis structure. Carbon forms double bonds with one oxygen atom and single bonds with the other oxygen atom in each carboxyl group.
Step-by-step explanation:
The orbitals used to form each indicated bond in citric acid (CHO) can be determined by looking at the Lewis structure of the compound. Citric acid is a tricarboxylic acid, meaning it has three carboxyl groups (-COOH) in its structure. Each carboxyl group is formed by a covalent bond between a carbon atom and an oxygen atom. In the case of citric acid, the carbon atom forms a double bond with one oxygen atom and a single bond with the other oxygen atom in each carboxyl group.
Therefore, the orbitals used to form the double bond are the carbon atom's sp^2 hybrid orbitals, while the orbitals used to form the single bond are the carbon atom's sp^3 hybrid orbitals. The oxygen atom in the carboxyl group forms a single bond with the carbon atom through one of its sp^3 hybrid orbitals.
Overall, citric acid has three carboxyl groups, so it has a total of three double bonds and three single bonds. Each double bond involves two carbon sp^2 hybrid orbitals and two oxygen p orbitals, while each single bond involves one carbon sp^3 hybrid orbital and one oxygen sp^3 hybrid orbital.