Question

The correct order of the thermal stability of hydrogen halides (H-X) is:

• A. \( \text{HI}>\text{HCl}>\text{HF}>\text{HBr} \)
• B. \( \text{HCl}<\text{HF}>\text{HBr}>\text{HI} \)
• C. \( \text{HF}>\text{HCl}>\text{HBr}>\text{HI} \)
• D. \( \text{HI}<\text{HBr}>\text{HCl}<\text{HF} \)

Hint:

The thermal stability of hydrogen halides increases with atomic size, which weakens the bond strength between hydrogen and halogen.

Answer 1

The Correct Option is A

Step 1: The thermal stability of hydrogen halides increases as we go down the group due to weaker H-X bonds.
Step 2: \( \text{HI} \) is the most stable due to the weakest bond, and \( \text{HF} \) is the least stable due to the strong H-F bond.

Final Answer: \[ \boxed{\text{HI}>\text{HCl}>\text{HF}>\text{HBr}} \]