Question

Choose all correct answers and explain your reason for each
The standard heats of formation of the hydrides of group VII elements are HF(-271),
HCl(-92), HBr(-36) These figures indicate that (1) HF is the least stable of them (2) HBr is
the most stable of them (3) HF is the most stable of them

Answer 1

A more negative standard heats of formation represent a more stable molecule. Thus, the most stable is HF.