Question

Which is the correct order of stability?

• A. HF $>$ HBr $>$ HCl $>$ HI
• B. HF $>$ HCl $>$ HBr $>$ HI
• C. HF $<$ HCl $<$ HBr $<$ HI
• D. HF $>$ HI $>$ HCl $>$ HBr

Answer 1

Answer: (A)

HF $>$ HBr $>$ HCl $>$ HI

Among hydrogen halides, $HF$ is the most stable.

The stability of the remaining hydrogen halides decreases in the order $HBr>HCl>HI$. $HI$ is so unstable that it gets easily decomposed when exposed to heat or light. The thermal stability of hydrogen halides depends on their bond enthalpy. Higher the bond enthalpy, higher is the stability.

Hence, option $A$ is correct.