iv. Dissociation constant of acetic acid is 1.8 × 10-5. Calculate percent dissociation of acetic acid in 0.01 M solution.
2. Answer the following in one sentence :
iv. Dissociation constant of acetic acid is 1.8 × 10-5. Calculate percent dissociation of acetic acid in 0.01 M solution.
Answer:-
Given:
- Dissociation constant (\(K_a\)) = \(1.8 \times 10^{-5}\),
- Concentration (\(c\)) = 0.01 M
To find:
- Percent dissociation
Formulae:
- \(K_a = \alpha^2c\)
- Percent dissociation = \(\alpha \times 100\)
Calculation:
\(c = 0.01\) M
= \(1 \times 10^{-2}\) M
Using formula (i),
Therefore, \(\alpha = \sqrt{\frac{K_a}{c}}\)
= \(\sqrt{\frac{1.8 \times 10^{-5}}{1 \times 10^{-2}}}\)
= \(\sqrt{1.8 \times 10^{-3}}\)
= \(\sqrt{18 \times 10^{-4}}\)
= \(4.242 \times 10^{-2}\)
Using formula (ii),
Percent dissociation = \(\alpha \times 100\)
= \(4.242 \times 10^{-2} \times 100\)
= \(4.242\%\)
Percent dissociation of 0.01 M acetic acid solution is 4.242%.