Final answer:
Balancing the half-reaction B(OH)₃ → BH₄⁻ in an acidic solution requires adding protons (H+ ions) to balance the hydrogen atoms and charges. The exact number of protons consumed depends on the balanced reaction.
Step-by-step explanation:
When balancing the half-reaction B(OH)₃ → BH₄⁻ in acidic solution, it involves a change in oxidation state and the consumption of protons (H+ ions). Balancing this reaction is a multi-step process which involves identifying changes in oxidation states and then balancing charges with electrons and balancing hydrogen atoms with protons (H+).
To balance the half-reaction, start by considering the changes in oxidation state for boron; then, add electrons to balance the charges. Since the question specifies an acidic solution, protons (H+ ions), rather than hydroxide ions (OH-), are used to balance the reaction further. The final step involves balancing the oxygen atoms, potentially by adding water molecules (H₂O). As a result, the number of protons consumed will correspond to the number needed to balance the charges and the hydrogen atoms in the equation.