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.
Na(23)+O(16)+H(1)=23+16+1=40
It is clear that X is sodium, Y is sodium hydroxide and Z is hydrogen. The reaction can be shown by following equation: 2Na+2H2O→2NaOH+H2+Heat
Hydrogen is a highly inflammable gas and hence it easily catches fire.