Which one of the following metals do not react with cold as well as hot water?
(a) Na
(b) Ca
(c) Mg
(d) Fe
Ans. (d)
Reactivity of metals with water is based on reactivity series.
Metals like (Na, K and Ca) react with cold water.
Magnesium (Mg) reacts with hot water but Zinc (Zn) and Iron (Fe) react with steam.
Metals like lead, copper, silver and gold do not react with water (or even steam).
Red hot iron reacts with steam to form iron oxide and hydrogen.