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KCET · Chemistry · Ionic Equilibrium

\(K_{a}\) values for acids \(\mathrm{H}_{2} \mathrm{SO}_{3}, \mathrm{HNO}_{2}, \mathrm{CH}_{3} \mathrm{COOH}\) and \(\mathrm{HCN}\) are respectively \(1.3 \times 10^{-2}\), \(4 \times 10^{-4}, 1.8 \times 10^{-5}\) and \(4 \times 10^{-10}\), which of the above acids produces stronger conjugate base in aqueous solution?

  1. A \(\mathrm{H}_{2} \mathrm{SO}_{3}\)
  2. B \(\mathrm{HNO}_{2}\)
  3. C \(\mathrm{CH}_{3} \mathrm{COOH}\)
  4. D \(\mathrm{HCN}\)
Verified Solution

Answer & Solution

Correct Answer

(D) \(\mathrm{HCN}\)

Step-by-step Solution

Detailed explanation

Lower the value of \(K_{a}\), lower will be the acidic strength and stronger will be the conjugate base. Therefore, among the given acids, HCN has the lowest \(K_{a}\) value (i.e. \(4 \times 10^{-10}\) ).
Hence, it is the strongest conjugate base.