Which one of the following metals produces hydrogen with cold water?

Metals exhibit varying degrees of reactivity with water based on their position in the reactivity series. Highly reactive alkali metals, such as sodium and potassium, react violently and vigorously even with cold water [1]. This exothermic reaction produces a metal hydroxide and evolves hydrogen gas, which often catches fire due to the intense heat released [1]. In contrast, magnesium reacts very slowly with cold water but more readily with steam. Metals like iron do not react with cold water at all, requiring steam to undergo a chemical change. Furthermore, metals situated at the bottom of the reactivity series, such as copper and silver, are considered unreactive and do not react with water in any form—cold, hot, or steam. Therefore, among the given options, only sodium produces hydrogen upon contact with cold water.

Sources

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