What is the formula for oxalate?

The formula for oxalate is correctly represented as C2O4(2-). Oxalate is a dianion formed from oxalic acid, which has two carboxyl groups (–COOH). These groups can lose protons, resulting in the oxalate ion that carries a -2 charge.

In the given formula, C2 indicates that there are two carbon atoms, and O4 indicates there are four oxygen atoms. The structure typically includes two carbon atoms bonded to four oxygen atoms, with specific bonding arrangements that ensure the overall charge of the ion is -2.

The other options represent different anions: CrO4(2-) is the chromate ion, SO3(2-) is the sulfite ion, and PO4(3-) is the phosphate ion. Each of these has its distinct composition and charge, making them separate from the oxalate ion and thus not applicable to the question regarding the oxalate formula.