An element X on reacting with oxygen forms an oxide X2O. This oxide dissolves in water and turns red litmus blue. State whether element X is a metal or a non – metal. Explain with proper example.

Ans. X is a metal like Na or K.

Sodium combines with oxygen, forms sodium oxide (Na₂O). Sodium oxide dissolves in water and forms an alkali, sodium hydroxide (NaOH). In sodium hydroxide, red litmus turns blue.

2Na	+	O­2	→	Na­2O
Sodium		Oxygen		Sodium Oxide
Na2O	+	H2O	→	2NaOH
Sodium oxide		water		Sodium hydroxide