(Originais Teachy 2023) - Question Hard of Chemistry

An aqueous solution of chromic acid, H2CrO4, is mixed with an aqueous solution of sodium sulfide, Na2S, resulting in the formation of sodium chromate, Na2CrO4, and sodium sulfate, Na2SO4. In a laboratory context, the reaction is observed as a redox process, where chromium undergoes a reduction from +6 to +3 and sulfur undergoes an oxidation from -2 to zero. Considering that the reaction occurs in an acidic medium and that the chromium (III) ion is the oxidizing agent, while the sulfide ion is the reducing agent, describe in detail the process of balancing the redox equation for the described reaction, including the identification of oxidizing and reducing agents, and justify your answer based on the principles of charge conservation and oxidation number variation.