Question

(a) A metal ‘A’ reacts violently with cold water and the gas evolved catches fire. Another metal ‘B’ when dipped in water starts floating. The metal ‘C’ does not react either with cold or hot water, but reacts with steam. The metal ‘D’ does not react with water at all. Identify the metals ‘A’, ‘B’, ‘C’ and ‘D’.

Hint:

Metals like potassium and sodium are highly reactive with water, magnesium reacts with steam, while noble metals like gold do not react with water.

Answer 1

A: Potassium (K)
B: Sodium (Na)
C: Magnesium (Mg)
D: Gold (Au) or any noble metal like Platinum (Pt)
- Metal ‘A’: Reacts violently with cold water, producing a flammable gas. Potassium reacts vigorously with water, generating hydrogen that ignites due to heat.
- Metal ‘B’: Floats on water. Sodium reacts with cold water, producing hydrogen bubbles that adhere to the metal, causing it to float.
- Metal ‘C’: Unreactive with cold or hot water, but reacts with steam. Magnesium does not react with cold/hot water but reacts with steam to form magnesium oxide and hydrogen.
- Metal ‘D’: Inert to water. Noble metals like gold and platinum do not react with water under normal conditions.