Pyrolusite, psilomelane and braunite are the ores of which of the following?

Correct answer: (a) Manganese

Explanation

Pyrolusite (MnO₂), psilomelane (a hydrated barium manganese oxide) and braunite (a manganese silicate) are all ores of manganese. Pyrolusite is the most important; it is used in dry cells and in steel making.

The main ores of the others are:

• iron: haematite, magnetite, siderite and limonite;
• copper: chalcopyrite (copper pyrites), cuprite and malachite;
• aluminium: bauxite itself is an ore, not a metal.