Question

Rank the following in order of decreasing acid strength in aqueous solution: HI, HOCl, HOBr, HOI.

A.HClO > HI > HBrO > HIO

B.HI > HClO > HBrO > HIO

C.HI > HIO > HBrO > HClO

D.HIO > HBrO > HClO > HI

E.HClO > HBrO > HI > HIO

Answer 1

Among all the given molecules HI is the strongest because I is larger. Due to its larger size it can easily donate H⁺.

In case of oxyacids, acidic strength depends upon the electronegativity of atom F, Cl or Br or I attached to O.in a group from top to bottom, electronegativity of these halogens decreases, polarity of OH bond decreases, acid strength decreases. It means that, more the electronegativity of the halogen atom, more the tendency to pull electron and weaker the O-H bond and hence proton (H+) can easily be removed.

Therefore option B is the correct answer. HI > HClO > HBrO > HIO

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