Magnesium does not decompose in

Options

(a) steam
(b) hot water
(c) cold water
(d) semi-hot water

Correct Answer:

cold water

Explanation:

Magnesium has a very slight reaction with cold water. The reaction soon stops because the magnesium hydroxide formed is almost insoluble in water and forms a barrier on the magnesium preventing further reaction. Mg + 2H₂O → Mg(OH)₂ + H₂.