Question

Which from following compounds has lowest thermal stability?

• A. \(\text{IBr}\)
• B. \(\text{BrCl}\)
• C. \(\text{BrF}\)
• D. \(\text{ClF}\)

Hint:

Stability falls as the bond becomes longer and weaker; IBr has the largest, weakest bond.

Answer 1

The Correct Option is A

Step 1: Compare bond lengths
I-Br is longer than Br-Cl, Br-F and Cl-F.

Step 2: Relate to stability
Longer bond means lower bond energy, so the compound decomposes most readily. That is IBr, option (A).

Final Answer:
IBr, with the longest and weakest bond, is least stable, option (A). \[ \boxed{\text{IBr}} \]