Question

When a metal X is treated with cold water, it gives a basic salt Y with molecular formula XOH (Molecular mass = 40) and liberates a gas Z which easily catches fire. Identify X, Y and Z and also write the reaction involved.

Answer 1

When sodium metal is treated with cold water, it gives a base sodium hydroxide and hydrogen gas is liberated which undergo explosive combustion reaction in an atmosphere of oxygen gas with a pop sound.
Hence, metal X is sodium, base Y is sodium hydroxide and gas Z is hydrogen gas.

`2"Na"("s") + 2"H"_2"O"("l") -> 2"NaOH"("aq") + "H"_2("g")`