Q53 / 200 · Manipal (MET) 2014 · Chemistry
Strongest conjugate base is
- Correct answerA$\mathrm{ClO}^{-}$
- B$\mathrm{ClO}_2^{-}$
- C$\mathrm{ClO}_3{ }^{-}$
- D$\mathrm{ClO}_4^{-}$
Solution
If acid is weak, its conjugate base is strong. Greater the oxidation number of Cl , stronger the acid and thus, weaker the conjugate base.
$\begin{aligned}
& \mathrm{HClO} \mathrm{HClO}_2 \mathrm{HClO}_3 \mathrm{HClO}_4
\end{aligned}$
Oxidation number of Cl and acid strength increases $\mathrm{ClO}^{-} \mathrm{ClO}_2^{-} \mathrm{ClO}_3^{-} \mathrm{ClO}_4^{-}$
Conjugate base strength increases. Hence, $\mathrm{ClO}^{-}$is the strongest base.
Oxidation number of Cl and acid strength increases $\mathrm{ClO}^{-} \mathrm{ClO}_2^{-} \mathrm{ClO}_3^{-} \mathrm{ClO}_4^{-}$
Conjugate base strength increases. Hence, $\mathrm{ClO}^{-}$is the strongest base.
Hence, the correct answer is option: 'A'.