Which group 17 element exhibits the least reactivity with hydrogen due to its bond strength?
Reactivity with hydrogen decreases down group 17 as H-X bond strength weakens. F forms the strongest H-F bond, making HF the least reactive among HF, HCl, HBr, and HI.
Ref: NCERT Class 11 Chemistry > Chapter 3: Classification of Elements and Periodicity in Properties > Topic: Anomalous Properties and Second Period and Chemical Reactivity