Final answer:
The conjugate base of an acid is formed when the acid donates a proton (H+) to a base. The formulas of the conjugate bases of HF, HPO42-, and CH3CH2OH are F-, PO43-, and CH3CH2O-, respectively.
Step-by-step explanation:
The conjugate base of an acid is formed when the acid donates a proton (H+) to a base. To find the formula of the conjugate base, we remove the proton from the acid.
For HF, the conjugate base is F-. Removing the H+ ion from HF leaves us with F-.
For HPO42-, the conjugate base is PO43-. Removing the H+ ions from HPO42- leaves us with PO43-.
For CH3CH2OH, the conjugate base is CH3CH2O-. Removing the H+ ion from CH3CH2OH leaves us with CH3CH2O-.