Calculate the percent dissociation of a weak mono-acidic base if its concentration is 0.02 M.
[ $\text{K}_b$ for weak mono-acidic base = $1.8 \times 10^{-5}$ ]

Question

Calculate the percent dissociation of a weak mono-acidic base if its concentration is 0.02 M. [ K_b for weak mono-acidic base = 1.8 × 10^ -5 ]

Quantrex Academy · Accepted Answer

Correct answer: C. 3\ \%

For a weak mono-acidic base, the degree of dissociation

\alpha

is given by the formula:

\alpha = \sqrt{\dfrac{K_b}{C}}

Substituting the given values:

K_b = 1.8 \times 10^{-5}

C = 0.02

M

\alpha = \sqrt{\dfrac{1.8 \times 10^{-5}}{0.02}}

\alpha = \sqrt{9 \times 10^{-4}}

\alpha = 3 \times 10^{-2}

Percent dissociation

= \alpha \times 100 = 3 \times 10^{-2} \times 100 = 3\ \%

Answer:

3\ \%

Calculate the percent dissociation of a weak mono-acidic base if...