What reduction process does SO42- undergo?

The sulfate ion (SO₄²⁻) undergoes a reduction process typically represented by the gain of electrons. When considering reduction, we look for a process where an ion or molecule gains electrons, which often corresponds to a decrease in oxidation state.

In many electrochemical processes, sulfate can be reduced to sulfite (SO₃²⁻) or to hydrogen sulfide (H₂S). The specific reduction process can involve the addition of protons (H⁺) along with electrons.

In the case of option B, the reduction of SO₄²⁻ involves gaining 2 protons (H⁺) and 2 electrons to form sulfite. This process is important because it reflects the basic principle in electrochemistry that reduction can involve not only the gain of electrons but also the incorporation of protons in solution, especially in an acidic environment.

Therefore, option B correctly describes a typical reduction pathway for the sulfate ion, where both electrons and protons play a crucial role in the chemical transformation. This aligns well with fundamental principles of redox reactions in electrochemistry.