The correct IUPAC name of K₂ MnO₄ is

Solution

Chemistry ma’am · 4 steps

Find manganese's oxidation state first, then remember the complex is an anion, so it ends in -ate.

1. Oxidation state. Each K is +1 and each O is -2. The compound is neutral, so 2(+1) + x + 4(-2) = 0, which gives x = +6. That is the (VI) in the name.
2. Name the ligand. The ligand is O²⁻, which current IUPAC rules call oxido. There are four of them, so the complex has tetraoxido.
3. Anion takes -ate. The complex [MnO₄]²⁻ is an anion, so the metal name ends in -ate: manganese becomes manganate. The cation is named first, as plain potassium. No prefix like di- is added, because the oxidation state already fixes how many K⁺ ions are needed.
4. So. Putting it together gives potassium tetraoxidomanganate(VI), which is option (a).

The idea to keep. For a complex salt, work out the metal's oxidation state, use -ido names for anionic ligands, and add -ate to the metal when the complex ion is negative.

Answer from the NTA final answer key. Solution by PrepWiser.