Final answer:
The next step before balancing the redox reaction is to ensure that the number of electrons transferred is the same in both half-reactions (option C). In the balanced redox reaction, there will be a total transfer of 6 electrons, not 3 (option D is incorrect).
Step-by-step explanation:
In addressing the question about balancing redox reactions, the next step after identifying the two half-reactions Au³⁺ → Au and I⁻ → I₂ is to ensure that the number of electrons transferred is the same in both half-reactions, which corresponds to answer option C. This is essential before determining the stoichiometric coefficients and balancing the overall chemical reaction.
The gold half-reaction (Au³⁺ → Au) involves a gain of three electrons (reduction), while the iodide half-reaction (I⁻ → I₂) involves a loss of two electrons (oxidation). To balance the charge for both half-reactions, they are multiplied by appropriate coefficients so that the number of electrons lost in oxidation equals the number of electrons gained in reduction. For example, multiplying the gold half-reaction by 2 and the iodide half-reaction by 3 would yield 6 electrons for both, balancing out the electron transfer.
Considering the balanced equations, we can determine that 6 electrons (3 electrons from each of the two gold atoms and 2 electrons for each of the three iodide ions) are involved in the fully balanced redox reaction. Therefore, answer option D (3 electrons) for question 2 is not correct as it does not consider the multiplication of the half-reactions. The correct answer would include 6 electrons being transferred when the redox reaction is balanced, reflecting both the reduction of Au³⁺ and the oxidation of I⁻.