Question

In group 14 elements, element X has lowest melting point. This on heating with steam gives a compound Y. What is Y?

• A. $\text{CO}_2$
• B. $\text{SiO}_2$
• C. $\text{GeO}_2$
• D. $\text{SnO}_2$

Hint:

Unlike Tin, Lead (Pb) does not react with steam easily because of the rapid formation of a protective oxide layer on its surface.
Tin reacts completely to form $\text{SnO}_2$.

Answer 1

The Correct Option is D

Step 1: Compare melting points across Group 14.
Carbon does not melt at ordinary pressure, silicon melts near 1687 K, germanium near 1211 K, lead near 601 K, and tin melts lowest of all at about 505 K, so X is tin.
Step 2: Recall how tin reacts with steam.
Unlike cold water, hot steam does react with tin, oxidising it to the +4 state and releasing hydrogen gas: \[ \text{Sn} + 2\,\text{H}_2\text{O(steam)} \rightarrow \text{SnO}_2 + 2\,\text{H}_2 \]
Step 3: Read off compound Y.
The solid product of this reaction is tin(IV) oxide.
Final answer: Option 4, Y is $\text{SnO}_2$.