The formula CHO3 doesn't correspond to a known chemical species. It's likely a typo.

Here's why:

* Carbon can't form five bonds: In CHO3, carbon would have to form five bonds (one to hydrogen, three to oxygen). Carbon typically forms four bonds.

* Oxygen's valency: Oxygen typically forms two bonds. In CHO3, one oxygen would need to form three bonds.

Let's consider some possibilities and their corresponding conjugate bases:

1. If you meant HCO3- (Bicarbonate ion):

* Conjugate base: CO3^2- (Carbonate ion)

2. If you meant CH3O3 (which is unlikely, as it doesn't exist):

* We can't determine the conjugate base because CH3O3 is not a valid chemical formula.

To accurately determine the conjugate base, please provide the correct chemical formula.