Question

The equivalent conductance of ${\displaystyle \frac{\text{M}}{36}}$ solution of a weak monobasic acid is 6 mho cm² equivalent⁻¹ and at infinite dilution is 400 mho cm² equivalent⁻¹. The dissociation constant of this acid is ____________.

विकल्प

• 1.25 × 10⁻⁶

• 6.25 × 10⁻⁶

• 1.25 × 10⁻⁴

• 6.25 × 10⁻⁵

Answer 1

The equivalent conductance of ${\displaystyle \frac{\text{M}}{36}}$ solution of a weak monobasic acid is 6 mho cm² equivalent⁻¹ and at infinite dilution is 400 mho cm² equivalent⁻¹. The dissociation constant of this acid is 6.25 × 10⁻⁶.

Explanation:

α = ${\displaystyle \frac{\Lambda }{{\Lambda }_{\circ }}=\frac{6}{400}}$

K_a = α²C

= ${\displaystyle \frac{6}{400}\times \frac{6}{400}\times \frac{1}{36}}$

= 6.25 × 10⁻⁶