COMEDK · Chemistry · 8. Ionic Equilibrium
In a \(0.2 \mathrm{M}\) aqueous solution, lactic acid is \(6.9 \%\) dissociated. The value of dissociation constant is
- A \(1.2 \times 10^{-4}\)
- B \(95 \times 10^{-4}\)
- C \(6.5 \times 10^{-4}\)
- D \(3.6 \times 10^{-2}\)
Answer & Solution
Correct Answer
(B) \(95 \times 10^{-4}\)
Step-by-step Solution
Detailed explanation
Given, \(\alpha=6.9 \%\) \(\therefore\) Degree of dissociation, \(\alpha=\frac{6.9}{100}\) \(\therefore \quad \alpha=0.069\) According to ostwald's dilution law, \(\begin{aligned} & K_a=\alpha^2 C=(0.069)^2 \times 0.2 \\ & K_a=9.5 \times 10^{-4} \end{aligned}\)
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