Cobalt, manganese and chromium are all metals. • Cobalt(II) oxide is reduced by carbon to give cobalt metal. • Manganese(II) oxide does not react with carbon. • Chromium(II) oxide does not react with carbon. • Chromium does not react with water. • Manganese reacts with water. What is the sequence of reactivity for these metals?
- Acobalt → chromium → manganese
- Bcobalt → manganese → chromium
- Cchromium → manganese → cobalt
- Dmanganese → chromium → cobalt