Question

Identify the incorrect statement from the following:

• A. The acidic strength of HX (X = F, Cl, Br and I) follows the order: HF > HCl > HBr > HI.
• B. Fluorine exhibits –1 oxidation state whereas other halogens exhibit +1, +3, +5 and +7 oxidation states also.
• C. The enthalpy of dissociation of F₂ is smaller than that of Cl₂.
• D. Fluorine is stronger oxidising agent than chlorine.

Answer 1

The Correct Option is A

The acidic strength of hydrogen halides (HX) ascends the group: \(HF<HCl<HBr<HI\). This progression is attributed to the diminishing bond strength of the H-X bond with increasing halogen atom size. A weaker bond facilitates greater dissociation of the hydrogen ion (H⁺), thereby yielding a stronger acid. Consequently, statement (1) is erroneous.

The remaining statements are accurate:

• Fluorine, being the most electronegative element, exclusively displays a -1 oxidation state. Conversely, other halogens can manifest multiple oxidation states: +1, +3, +5, and +7.
• The bond dissociation enthalpy of F₂ is lower than that of Cl₂, attributable to pronounced electron-electron repulsion between lone pairs in the compact fluorine molecule.
• Fluorine surpasses chlorine as a stronger oxidizing agent owing to its superior electronegativity and smaller atomic radius.