Question

An unknown element X reacts in air to form its oxide Y. This Y dissolves in water which turns blue litmus into red. Predict the nature of oxide ‘Y’ and tell whether ‘X’ is a metal or a non-metal? Name two elements that behave like ‘X’.

Answer 1

Oxide Y is an acidic oxide formed from the reaction of non-metal element X with air; common non-metals forming acidic oxides include sulfur and carbon.

Step-by-step explanation:

If oxide Y dissolves in water and turns blue litmus to red, it suggests that Y is an acidic oxide. This behavior indicates that element X, which reacts with air to form Y, must be a non-metal. Oxides that dissolve in water to form acidic solutions are characteristic of non-metals due to their higher electronegativities and covalent bonding with oxygen.

In contrast, metals typically form basic oxides, which do not turn blue litmus red. Two non-metal elements that can form acidic oxides similar to X are sulfur (S) and carbon (C), which react with oxygen to form sulfur dioxide (SO2) and carbon dioxide (CO2), respectively; both gases dissolve in water to form acidic solutions.