Question

Which from following is the general formula of compound obtained when lanthanoid (Ln) reacts with carbon at elevated temperature?

• A. LaC\(_2\)
• B. LaC\(_3\)
• C. LaC\(_2\)Cl
• D. LaCl\(_3\)

Hint:

When lanthanides react with carbon, they typically form lanthanide carbides like LaC\(_2\) at elevated temperatures.

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
We need the formula for the carbide formed by lanthanoid elements.
Step 2: Detailed Explanation:
When lanthanoids (Ln) react with carbon at very high temperatures (about 2500 K), they form stable carbides.
The most common and characteristic formula for these dicarbides is \( \text{LnC}_2 \).
These compounds typically contain the \( \text{C}_2^{2-} \) (acetylide) ion.
Step 3: Final Answer:
The general formula is \( \text{LnC}_2 \).