Which one of the following metals does NOT react with cold water?

The reactivity of metals with water depends on their position in the activity series. Highly reactive alkali metals like potassium (K) and sodium (Na) react violently and vigorously with cold water, often producing enough heat to ignite the evolved hydrogen gas [1]. Calcium (Ca), while less violent than sodium, still reacts steadily with cold water to form calcium hydroxide and hydrogen bubbles [1]. In contrast, magnesium (Mg) has almost no reaction with cold water. It is considered less reactive and requires hot water or steam to react significantly. When magnesium reacts with hot water, it forms magnesium hydroxide, and with steam, it produces magnesium oxide and hydrogen gas [1]. Therefore, among the given options, magnesium is the metal that does not react with cold water.

Sources

1. [1] Science , class X (NCERT 2025 ed.) > Chapter 3: Metals and Non-metals > Activity 3.10 > p. 43