JEE Advanced 2017 · Paper 1 · Chemistry Q3

ChemistryMultiple correct+4 / -2Question 21 of 54

The correct statement(s) about the oxoacids, $\ce{HClO4}$ and $\ce{HClO}$ , is(are)

The central atom in both

\ce{HClO4}

and

\ce{HClO}

sp^3

hybridized

\ce{HClO4}

is more acidic than

\ce{HClO}

because of the resonance stabilization of its anion

\ce{HClO4}

is formed in the reaction between

\ce{Cl2}

and

\ce{H2O}

The conjugate base of

\ce{HClO4}

is weaker base than

\ce{H2O}

Answer and worked solution

Official answer: A, B, D

(A) Cl in $\ce{HClO4}$ has 4 σ bonds. Cl in HOCl has 1 σ bond and 3 lone pairs. Both are $sp^3$ . True.
(B) $\ce{ClO4-}$ spreads its charge over four equivalent O atoms by resonance, so $\ce{HClO4}$ is far stronger. True.
(C) $\ce{Cl2 + H2O -> HCl + HOCl}$ . Perchloric acid does not form. False.
(D) $\ce{HClO4}$ is a stronger acid than $\ce{H3O+}$ , so $\ce{ClO4-}$ is a weaker base than $\ce{H2O}$ . True.

(A), (B), (D)

Topics:Oxoacids Group 17 Hybridisation

JEE Advanced 2017 · Paper 1, Chemistry question 3