HF is a weaker acid than HI, even though fluorine is more electronegative than iodine-explain.

Explanation

1. The electronegativity of fluorine is much higher than iodine. Hence, the H - F bond is more polar than the H - I bond. The hydration enthalpy of smaller `F^(-)` ion is greater than that of larger `I^(-)` ion. So, HF is expected to be the stronger acid than HI which is not the case. It is because the bond dissociation enthalpy of H - F bond is much higher than that of H - I bond which dissociates more easily to release `H^(+)` ion.
2. In aqueous solutions, the, `F^(-)` ion produced on dissociation of HF, gives bifluoride ion `(HF_(2)^(-))` through hydrogen bonding with the undissociated HF molecule. This contributes to the least acidic property of HF.