Question

The dissociation constant of weak monoacidic base is \(1.8 \times 10^{-5}\). Calculate the degree of dissociation in \(0.02 \text{ M}\) solution.

• A. 0.03
• B. 0.04
• C. 0.02
• D. 0.01

Hint:

Weak electrolyte: \(\alpha = \sqrt{\frac{K}{C}}\)

Answer 1

The Correct Option is A

Concept:
For weak electrolyte: \[ K = C\alpha^2 \]

Step 1: Given. \[ K = 1.8 \times 10^{-5}, \quad C = 0.02 \]

Step 2: Substitute. \[ \alpha^2 = \frac{1.8 \times 10^{-5}}{0.02} = 9 \times 10^{-4} \]

Step 3: Calculate. \[ \alpha = \sqrt{9 \times 10^{-4}} = 3 \times 10^{-2} = 0.03 \] Conclusion: \[ \text{Degree of dissociation = 0.03} \]