Which one of the following metals does NOT react with cold water to liberate hydrogen gas ?

The reaction of metals with water depends on their position in the chemical reactivity series. Potassium (A) and Sodium (D) are highly reactive alkali metals that react violently with cold water to produce metal hydroxides and hydrogen gas. Calcium (C) also reacts with cold water, though the reaction is less vigorous, and the hydrogen bubbles formed cause the metal to float.

Iron (B), however, is much less reactive. It does not react with cold or hot water. Iron only reacts when it comes into contact with steam (water vapor) to form iron oxide and liberate hydrogen gas. Metals like Aluminum and Zinc also share this property of requiring steam for a reaction, whereas noble metals like Gold, Silver, and Copper do not react with water in any form.